With the merciful, etc. David here prosecutes the same subject. In considering the grace of God by which he had been delivered, he brings it forward as a proof of his integrity, and thus triumphs over the unfounded and disgraceful calumnies of his enemies. Hypocrites, I confess, are also accustomed to act in the same way; for prosperity and the success of their affairs so elates them that they are not ashamed proudly to vaunt themselves not only against men, but even against God. As such persons, however, openly mock God, when, by his long-suffering, he allures them to repentance, their wicked and unhappy presumption has no resemblance to the boasting by which we here see David encouraging himself. He does not abuse the forbearance and mercy of God by palliating or spreading a specious varnish over his iniquities, because God bears with them; but having, by the manifold aids he had received from God, experienced beyond doubt that he was merciful to him, he justly viewed them as evident testimonies of the divine favor towards him. And we ought to mark well this difference between the ungodly and the faithful, namely, that the former, intoxicated with prosperity, unblushingly boast of being acceptable to God, while yet they disregard him, and rather sacrifice to Fortune, and make it their God; whereas the latter in their prosperity magnify the grace of God, from the deep sense of his grace with which their consciences are affected. Thus David here boasts that God had succoured him on account of the justice of his cause. For, in the first place, we must adapt the words to the scope of the whole discourse, and view them as implying that God, in so often delivering an innocent man from death, when it was near him, showed, indeed, that he is merciful towards the merciful, and pure towards the pure. In the second place, we must view the words as teaching the general doctrine, that God never disappoints his servants, but always at length deals graciously with them, provided they wait for his aid with meekness and patience. To this purpose Jacob said, in Genesis 30:33, "God will make my righteousness to return upon me." The scope of the discourse is, that the people of God should entertain good hope, and encourage themselves to practice uprightness and integrity, since every man shall reap the fruit of his own righteousness. The last clause of the 26th verse, where it is said, With the perverse thou wilt show thyself perverse, seems to convey a meaning somewhat strange, but it does not imply any thing absurd; yea, rather, it is not without good reason that the Holy Spirit uses this manner of speaking; for he designs thereby to awaken hypocrites and the gross despisers of God, who lull themselves asleep in their vices without any apprehension of danger. We see how such persons, when the Scripture proclaims the sore and dreadful judgments of God, and when also God himself denounces terrible vengeance, pass over all these things, without giving themselves any trouble about them. Accordingly, this brutish, and, as it were, monstrous stupidity which we see in men, compels God to invent new forms of expression, and, as it were, to clothe himself with a different character. There is a similar sentence in Leviticus 26:21-24, where God says, "And if ye walk contrary unto [or perversely with] me, then will I also walk contrary unto [or perversely or roughly, or at random against] you;" as if he had said, that their obstinacy and stubbornness would make him on his part forget his accustomed forbearance and gentleness, and cast himself recklessly or at random against them. We see, then, what the stubborn at length gain by their obduracy; it is this, that God hardens himself still more to break them in pieces, and if they are of stone, he causes them to feel that he has the hardness of iron. Another reason which we may assign for this manner of speaking is, that the Holy Spirit, in addressing his discourse to the wicked, commonly speaks according to their own apprehension. When God thunders in good earnest upon them, they transform him, through the blind terrors which seize upon them, into a character different from his real one, inasmuch as they conceive of nothing as entering into it but barbarity, cruelty, and ferocity. We now see the reason why David does not simply attribute to God the name and office of judge, but introduces him as armed with impetuous violence, for resisting and overcoming the perverse, according as it is said in the common proverb, A tough knot requires a stout wedge.

With the merciful - From the particular statement respecting the divine dealings with himself the psalmist now passes to a general statement (suggested by what God had done for him) in regard to the general principles of the divine administration. That general statement is, that God deals with men according to their character; or, that he will adapt his providential dealings to the conduct of men. They will find him to be such toward them as they have shown themselves to be toward him. The word merciful refers to one who is disposed to show kindness or compassion to those who are guilty, or to those who injure or wrong us.
Thou wilt show thyself merciful - Thou wilt evince toward him the same character which he shows to others. It is in accordance with this that the Saviour teaches us to pray, "And forgive us our debts, as we forgive our debtors," Matthew 6:12. And in accordance also with this he said, "For if ye forgive men their trespasses, your heavenly Father will also forgive you: but if ye forgive not men their trespasses, neither will your Father forgive your trespasses," Matthew 6:14-15.
With an upright man - literally, a perfect man. See Job 1:1, where the same word is used in the original, and rendered perfect. The idea is that of a man who is consistent, or whose character is complete in all its parts. See the note at Job 1:1.
Thou wilt show thyself upright - Thou wilt deal with him according to his character. As he is faithful and just, so will he find that he has to do with a God who is faithful and just.

With the merciful thou wilt show thyself merciful - Thou wilt deal with men as they deal with each other. This is the general tenor of God's providential conduct towards mankind; well expressed by Mr. Pope in his universal prayer: -
"Teach me to feel another's wo;To hide the fault I see:
The mercy I to others show,That mercy show to me."
It is in reference to this that our Lord teaches us to pray: "Forgive us our trespasses, as we forgive them that trespass against us." If we act feelingly and mercifully towards our fellow creatures, God will act tenderly and compassionately towards us. The merciful, the upright, and the pure, will ever have the God of mercy, uprightness, and purity, to defend and support them.

With the (t) merciful thou wilt shew thyself merciful; with an upright man thou wilt shew thyself upright;
(t) Here he speaks of God according to our capacity, who shows mercy to his and punishes the wicked, as is also said in (Leviticus 26:21, Leviticus 26:24).

With the merciful thou wilt show thyself merciful,.... The merciful man is the good, gracious, holy, and godly man, as the word (z) here used signifies, and is sometimes rendered; one that has received grace and mercy from the Lord, and has principles of grace and goodness wrought in him, and is kind and merciful to others, both to their souls and bodies; and to such men God shows himself merciful: not that they are first merciful to others, and then he is so to them, for it is just the reverse; nor is their mercifulness the cause or condition of his, for he has mercy on whom he will have mercy; but to such he shows fresh mercy, and bestows more grace upon them; they find grace and mercy with him now, and will do hereafter; see Matthew 5:7. This may be applied to Christ, all whose ways are mercy and truth; he saw the estate his people would come into; he pitied their case, and became their surety in eternity; he betrothed them to himself in loving kindness and tender mercies; and undertook to feed the flock of slaughter, even the poor of the flock; having, through his merciful lovingkindness, assumed human nature, he went about doing good to the souls and bodies of men; he healed the diseased and fed the hungry, and had compassion on the ignorant, and them that were out of the way; and, as a merciful high priest, he bore the sins and sorrows of his people; and in his love and pity redeemed them, and continues to sympathize with them in all their afflictions and temptations; and though no mercy was shown him while he was suffering for them, for God spared him not, but awoke the sword of justice against him, and used him with the utmost rigour and severity; yet satisfaction being made, he did not leave him in the grave, nor suffer his holy, good, and merciful One to see corruption; but raised him from the dead, prevented him with the blessings of his goodness, and set upon his head a crown of honour and glory;
with an upright man thou wilt show thyself upright; an upright man, as the word (a) used signifies, is a perfect man, not absolutely, but comparatively; not in himself, but in Christ; perfect with a perfection of parts, but not of degrees; he is one that is upright in heart, sincere and without hypocrisy; an Israelite indeed, whose faith, hope, and love, are undisguised; he is a man of integrity, a faithful man, faithful to God, his cause and interest, his word and ordinances, and is faithful with the saints; he walks, uprightly according to the rule of God's word, and by faith in Christ; and to such upright men God shows himself upright, or faithful, by keeping his covenant with them, fulfilling his promises to them, and not suffering one good thing to fail he has given them reason to expect from him. This may also be interpreted of Christ, who is in the highest and fullest sense perfect, upright, and sincere, and faithful to him that appointed him; and as he has been faithful in all his covenant engagements with his Father, so his Father has been faithful to him in making good all he promised him; both with respect to his own glory, and the happiness of his people; see Isaiah 53:10.
(z) "benigno", Vatablus, Junius & Tremellius; "bono", Gejerus, some in Vatablus; "qui bonitati studet", Tigurine version; "pio", Munster, Cocceius, Michaelis; "gracious saint", Ainsworth. (a) "perfecto", Pagninus, Montanus; so Ainsworth.

God renders to men according to their deeds in a penal, not vindictive, sense (Leviticus 26:23-24).
merciful--or, "kind" (Psalm 4:3).

Upright - Thou metest to every one the same measure, which he meteth out to others; and therefore thou wilt perform mercy and truth, to those who are merciful and true to others.