If his children shall forsake my law. The prophet proceeds yet farther, declaring, that although the posterity of David should fall into sin, yet God had promised to show himself merciful towards them, and that he would not punish their transgressions to the full extent of their desert. Moreover, to give the promise the greater efficacy, he always introduces God speaking, as if he presented to him a request corresponding with the precise words and express articles of his covenant. [1] It was very necessary that this should be added; for so easily do we slide into evil, and so prone are we to continual falls, that unless God, in the exercise of his infinite mercy, pardoned us, there would not be a single article of his covenant which would continue steadfast. God, therefore, seeing that it could not be otherwise, but that the posterity of David, in so far as it depended upon themselves, would frequently fall from the covenant, by their own fault, has provided a remedy for such cases, in his pardoning grace. Farther, as it is profitable for men to be subjected to divine correction, he does not promise that he will allow them to escape unpunished, which would be to encourage them in their sins; but he promises, that in his chastisements he will exercise a fatherly moderation, and will not execute vengeance upon them to the full extent which their sins deserve. It is also to be observed, that he promises pardon, not only for light offenses, but also for great and aggravated sins. It is not without cause that he uses these forms of expression, to forsake his law, to violate his statutes, not to walk in his judgments, and not to keep his commandments Nor is it without cause that he uses the word transgression, or perfidiousness, and iniquity. We see, then, that the patience and lenity of God, by which he reconciles to himself the posterity of David, is extended even to sins of the most heinous and aggravated description. This passage teaches us, that when God adopts men into his family, they do not forthwith completely lay aside the flesh with its corruptions, as is held by some enthusiasts, who dream, that as soon as we are grafted into the body of Christ, all the corruption that is in us must be destroyed. Would to God that we could all on a sudden change our nature, and thus exhibit that angelic perfection which they require! But as it is quite apparent, that we are far from such an attainment, so long as we carry about with us this tabernacle of flesh, let us bid adieu to that devilish figment, and let us all betake ourselves to the sanctuary of forgiveness, which is at all times open for us. God, unquestionably, is speaking of the household of his Church; and yet it is declared, with sufficient plainness, in the promise which he makes of pardoning their offenses, that they will transgress and be guilty of revolting from him. To limit what is here said to the ancient people of Israel, is an exposition not only absurd, but altogether impious. In the first place, I take it as a settled point, which we have already had occasion often to consider, that this kingdom was erected to be a figure or shadow in which God might represent the Mediator to his Church: and this can be proved, not only from the testimony of Christ and the apostles, but it may also be clearly and indubitably deduced from the thing considered in itself. If we set Christ aside, where will we find that everlasting duration of the royal throne of which mention is here made? The second from David, in the order of succession, was despoiled of the greater part of the kingdom, so that out of twelve tribes he retained scarcely one tribe and a half. Afterwards, how many losses did this kingdom thus greatly reduced sustain, and by how many calamities was it defaced, until at length the king and the whole body of the people were dragged into captivity, with the utmost ignominy and reproach? And I pray you to consider where was the dignity of the throne, when the king, after his sons were put to death before his eyes, was himself treated as a criminal? (2 Kings 25:7.) The Jews were indeed afterwards permitted to dwell in their own country; but it was without the honor and title of a kingdom. Accordingly, Ezekiel (Ezekiel 21:27) declares thrice, that the crown shall be laid in the dust, "until he come whose right it is." The obvious conclusion then is, that perpetuity, as applied to this kingdom, can be verified in Christ alone. And, in fact, what access could the Jews of old time have had to God, or what access could we in the present day have to him, did not the Mediator come between us and him, to cause us find favor in his sight? It now remains that we apply to ourselves the qualities of this kingdom of which we have been speaking. As its everlasting duration leads us to the hope of a blessed immortality, and its invincible strength inspires our minds with tranquillity, and prevents our faith from failing, notwithstanding all the efforts which Satan may put forth against us, and notwithstanding the numerous forms of death which may surround us; so the pardon which is here promised belongs to the spiritual kingdom of Christ: and it may be equally gathered from this passage, that the salvation of the Church depends solely upon the grace of God, and the truth of his promises. If it is objected, that those who are regenerated by the Spirit of God never totally fall away, because the incorruptible seed of the word abides in them, I grant that this is an important truth. It is not, however, a total apostasy which is here spoken of -- not such as implies the entire extinction of godliness in the individual chargeable with it. But it sometimes happens that the faithful cast off the yoke of God, and break forth into sin in such a manner, as that the fear of God seems to be extinguished in them; and such being the case, it was necessary that He should promise the pardon even of heinous sins, that they might not upon every fall be overwhelmed with despair. Thus David seemed, to outward appearance, to be wholly deprived of the Spirit of God, whom he prays to be restored to him. The reason why God leaves hope of pardon even for detestable and deadly transgressions is, that the enormity of our sins may not keep us back or hinder us from seeking reconciliation with him. From this, we are led to condemn the undue severity of the fathers, who scrupled to receive to repentance those who had fallen for the second or third time. Due care must indeed be taken lest, by too great forbearance, loose reins should be given to men to commit iniquity; but there is no less danger in an extreme degree of rigour. It is to be observed, that when God declares that he will show himself merciful towards sinners, who have violated his law, and broken his commandments, he purposely employs these odious terms to excite our hatred and detestation of sin, and not to entice us to the commission of it. Still, however, we must understand the passage as amounting to this, That although the faithful may not in every instance act in a manner worthy of the grace of God, and may therefore deserve to be rejected by him, yet he will be merciful to them, because remission of sins is an essential article promised in his covenant. And, indeed, as God in his law requires us to perform what exceeds our power, all that he promises in it is of no avail to us, to whom it can never be accomplished. Hence Paul, in Romans 4:14, affirms, "If the inheritance come by the law, faith is made void, and the promise made of none effect." To this also belong these words of Jeremiah, "Behold, the days come, saith the Lord, that I will make a new covenant with the house of Israel, and with the house of Judah; not according to the covenant that I made with their fathers, in the day that I took them by the hand to bring them out of the land of Egypt; (which my covenant they brake, although I was an husband unto them, saith the Lord;) but this shall be the covenant that I will make with the house of Israel: After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. I will forgive their iniquity, and I will remember their sin no more." (Jeremiah 31:31-34) Farther, since God does not adopt us as his children, to encourage us to take liberty to commit sin with the greater boldness, mention is here made at the same time of chastisement, by which he shows that he hates the sins of his children, and, warning them of what they have deserved in offending him, invites and exhorts them to repentance. This fatherly chastisement then, which operates as medicine, holds the medium between undue indulgence, which is an encouragement to sin, and extreme severity, which precipitates persons into destruction. Here the inspired writer adverts to the prophecy recorded in 2 Samuel 7:14, where God declares that in chastising his own people, he will proceed after the manner of men -- "If he commit iniquity, I will chasten him with the rod of men, and with the stripes of the children of men." (2 Samuel 7:14) God there speaks of his chastising his people after the manner of men, either because the anger of a father in correcting his children proceeds from love, -- for he sees that otherwise he would fail in promoting their good; or it contains a contrast between God and men, implying, that in the task of chastising he will proceed with moderation and gentleness; for, were he to put forth his strength, he would immediately bring us to nothing, yea, he could do this simply by moving one of his fingers. The scope of both passages undoubtedly is, that whenever God punishes the sins of true believers, he will observe a wholesome moderation; and it is therefore our duty to take all the punishments which he inflicts upon us, as so many medicines. On this point, the Papists have egregiously blundered. Not understanding the true end and fruit of chastisements, they have imagined that God proceeds herein as if avenging himself upon sinners. Whence arose their satisfactions, and from these again proceeded pardons and indulgences, by which they endeavored to redeem themselves from the hand and vengeance of God. But God has nothing else in view than to correct the vices of his children, in order that, after having thoroughly purged them, he may restore them anew to his favor and friendship; according to the words of Paul in 1-Corinthians 11:33, which affirm that the faithful "are chastened of the Lord, that they should not be condemned with the world." For this reason, lest they should be overwhelmed with the weight of chastisement, he restrains his hand, and makes considerate allowance for their infirmity. Thus the promise is fulfilled, That he does not withdraw his loving-kindness from his people, even when he is angry with them; for, while he is correcting them for their profit and salvation, he does not cease to love them. It is, however, to be observed, that there is a change of person in the words. After it is said, If his children shall forsake my law, etc., it is at length subjoined, My loving-kindness or mercy will I not withdraw from Him. It ought surely to have been said, them instead of him, since it is children in the plural number who are before spoken of. But it is very probable that this form of expression is purposely employed to teach us that we are reconciled to God only through Christ; and that if we would expect to find mercy, we must seek for it from that source alone. What follows in the end of the verse, I will not suffer my faithfulness to fail, is more emphatic than if it had been said that God will be true to what he has said. It is possible that God's promise may fail of taking effect, and yet he may continue faithful. For example, the law is true and holy, and yet of what advantage is it to us that salvation is promised in the law, when no human being can ever obtain salvation by it? God then in this passage leads us farther; promising that his covenant shall be steadfast and effectual, not only because he will be faithful on his part, but also because he will keep his people from falling away through their own inconstancy.

Footnotes

1 - "The whole passage, beginning with I have laid help,' in verse 19, to the end of verse 37, may be considered as a paraphrase of what God had said unto David, (2 Samuel 7:8, etc.,) through the mouth of Nathan. The promises herein recited, we know from history, had their fulfillment only in Jesus Christ. The Psalmist, therefore, in the next subsequent verses, contemplating the calamities of his nation, indulges in the language of complaint." -- Cresswell.

If his children - His posterity; his successors on the throne.
Forsake my law - If they are not regulated by it in the administration of their government, and in their private lives. It is here supposed that they might forsake his law, or fail to observe it; but still there is the assurance that the power would not depart permanently from the successors of David, but that it would be restored ultimately to that line, and be permanent and eternal.
And walk not in my judgements - And do not obey my commandments.

If his children forsake my law - See the notes on 2-Samuel 7:13, where this and some of the following verses are explained.

If his children forsake my law,.... The same with the seed before mentioned, the children of the Messiah: it is not said "if he forsakes", which cannot be supposed of Christ, because he knew no sin, nor did any; which yet might be supposed of David, had he been literally meant; but not he, nor his natural children, but the spiritual seed of mystical David, are here designed, who may sin, and do sin, of which there is too much proof and evidence; and who sin not only through infirmity, but sometimes very grossly, and which sins are here expressed by various phrases: they sometimes "forsake the law of God"; do not attend to it, as they should, as the rule of their walk and conversation; are remiss in their observance of it, and obedience to it, and transgress its precepts; or his "doctrine" (h), even the doctrine of the Gospel; which may be said to be forsaken when men grow indifferent to it; go off from it in any measure, drop their profession of it, or hold it remissly, or become careless in their attendance on it: forsaking the assembling together to hear it, in some sense, is a forsaking of it; and this the Lord takes notice of, and resents, in his people:
and walk not in my judgments; those laws of his house by which he judges, regulates, and governs his people; by which they are directed by him, as their Judge and Lawgiver, how to behave themselves in the church of God; and in which they are to walk, and continue in the observance of; and so to do is to walk as becomes the Gospel, and worthy of their calling; but to do otherwise is to walk disorderly; and such are cognizable by the Lord, and by his people.
(h) "verbum meaum revelatum", Gejerus; "legem et doctrinam meam", Michaelis.

Now follows the paraphrase of 2-Samuel 7:14, that the faithlessness of David's line in relation to the covenant shall not interfere with (annul) the faithfulness of God - a thought with which one might very naturally console one's self in the reign of Rehoboam. Because God has placed the house of David in a filial relationship to Himself, He will chastise the apostate members as a father chastises his son; cf. Proverbs 23:13. In 1-Chronicles 17:13 the chronicler omits the words of 2-Samuel 7:14 which there provide against perverted action (העוות) on the part of the seed of David; our Psalm proves their originality. But even if, as history shows, this means of chastisement should be ineffectual in the case of individuals, the house of David as such will nevertheless remain ever in a state of favour with Him. In Psalm 89:34 חסדּי לא־אפיר מעמּו corresponds to וחסדּי־לא־יסוּר ממּנּוּ in 2-Samuel 7:15 (lxx, Targum): the fut. Hiph. of פרר is otherwise always אפר; the conjecture אסיר is therefore natural, yet even the lxx translators (ου ̓ μὴ διασκεδάσω) had אפיר before them. שׁקּר בּ as in Psalm 44:18. The covenant with David is sacred with God: He will not profane it (חלּל, to loose the bonds of sanctity). He will fulfil what has gone forth from His lips, i.e., His vow, according to Deuteronomy 23:24 [23], cf. Numbers 30:3 [2]. One thing hath He sworn to David; not: once = once for all (lxx), for what is introduced by Psalm 89:36 (cf. Psalm 27:4) and follows in Psalm 89:37, Psalm 89:38, is in reality one thing (as in Psalm 62:12, two). He hath sworn it per sanctitatem suam. Thus, and not in sanctuario meo, בּקדשׁי in this passage and Amos 4:2 (cf. on Psalm 60:8) is to be rendered, for elsewhere the expression is בּי, Genesis 22:16; Isaiah 45:23, or בּנפשׁו, Amos 6:8; Jeremiah 51:14, or בּשׁמי, Jeremiah 44:26, or בּימינו, Isaiah 62:8. It is true we do not read any set form of oath in 2 Sam. 7, 1 Chr. 17, but just as Isaiah, Isaiah 54:9, takes the divine promise in Genesis 8:21 as an oath, so the promise so earnestly and most solemnly pledged to David may be accounted by Psalm-poesy (here and in Psalm 132:11), which reproduces the historical matter of fact, as a promise attested with an oath. With אם in Psalm 89:36 God asserts that He will not disappoint David in reference to this one thing, viz., the perpetuity of his throne. This shall stand for ever as the sun and moon; for these, though they may one day undergo a change (Psalm 102:27), shall nevertheless never be destroyed. In the presence of 2-Samuel 7:16 it looks as if Psalm 89:38 ought to be rendered: and as the witness in the clouds shall it (David's throne) be faithful (perpetual). By the witness in the clouds one would then have to understand the rainbow as the celestial memorial and sign of an everlasting covenant. Thus Luther, Geier, Schmid, and others. But neither this rendering, nor the more natural one, "and as the perpetual, faithful witness in the clouds," is admissible in connection with the absence of the כּ of comparison. Accordingly Hengstenberg, following the example of Jewish expositors, renders: "and the witness in the clouds is perpetual," viz., the moon, so that the continuance of the Davidic line would be associated with the moon, just as the continuance of the condemned earth is with the rainbow. But in what sense would the moon have the name, without example elsewhere, of witness? Just as the Book of Job was the key to the conclusion of Ps 88, so it is the key to this ambiguous verse of the Psalm before us. It has to be explained according to Job 16:19, where Job says: "Behold in heaven is my witness, and my surety in the heights." Jahve, the אל נאמן (Deuteronomy 7:9), seals His sworn promise with the words, "and the witness in the sky (ethereal heights) is faithful" (cf. concerning this Waw in connection with asseverations, Ew. 340, c). Hengstenberg's objection, that Jahve cannot be called His own witness, is disposed of by the fact that עד frequently signifies the person who testifies anything concerning himself; in this sense, in fact, the whole Tra is called עדוּת ה (the testimony of Jahve).