For God is not unrighteous, etc. These words signify as much as though he had said, that from good beginnings he hoped for a good end. But here a difficulty arises, because he seems to say that God is bound by the services of men: "I am persuaded," he says, "as to your salvation, because God cannot forget your works." He seems thus to build salvation on works, and to make God a debtor to them. And the sophists, who oppose the merits of works to the grace of God, make much of this sentence, "God is not unrighteous." For they hence conclude that it would be unjust for him not to render for works the reward of eternal salvation. To this I briefly reply that the Apostle does not here speak avowedly of the cause of our salvation, and that therefore no opinion can be formed from this passage as to the merits of works, nor can it be hence determined what is due to works. The Scripture shows everywhere that there is no other fountain of salvation but the gratuitous mercy of God: and that God everywhere promises reward to works, this depends on that gratuitous promise, by which he adopts us as his children, and reconciles us to himself by not imputing our sins. Reward then is reserved for works, not through merit, but the free bounty of God alone; and yet even this free reward of works does not take place, except we be first received into favor through the kind mediation of Christ. We hence conclude, that God does not pay us a debt, but performs what he has of himself freely promised, and thus performs it, inasmuch as he pardons us and our works; nay, he looks not so much on our works as on his own grace in our works. It is on this account that he forgets not our works, because he recognizes himself and the work of his Spirit in them. And this is to be righteous, as the Apostle says, for he cannot deny himself. This passage, then, corresponds with that saying of Paul, "He who has begun in you a good work will perfect it." (Philippians 1:6.) For what can God find in us to induce him to love us, except what he has first conferred on us? In short, the sophists are mistaken in imagining a mutual relation between God's righteousness and the merits of our works, since God on the contrary so regards himself and his own gifts, that he carries on to the end what of his own goodwill he has begun in us, without any inducement from anything we do; nay, God is righteous in recompensing works, because he is true and faithful: and he has made himself a debtor to us, not by receiving anything from us; but as Augustine says, by freely promising all things. [1] And labor of love, etc. By this he intimates that we are not to spare labor, if we desire to perform duty towards our neighbors; for they are not only to be helped by money, but also by counsel, by labor, and in various other ways. Great sedulity, then, must be exercised, many troubles must be undergone, and sometimes many dangers must be encountered. Thus let him who would engage in the duties of love, prepare himself for a life of labor. [2] He mentions in proof of their love, that they had ministered and were still ministering to the saints. We are hence reminded, that we are not to neglect to serve our brethren. By mentioning the saints, he means not that we are debtors to them alone; for our love ought to expand and be manifested towards all mankind; but as the household of faith are especially recommended to us, peculiar attention is to be paid to them; for as love, when moved to do good, has partly a regard to God, and partly to our common nature, the nearer any one is to God, the more worthy he is of being assisted by us. In short, when we acknowledge any one as a child of God, we ought to embrace him with brotherly love. By saying that they had ministered and were still ministering, he commended their perseverance; which in this particular was very necessary; for there is nothing to which we are more prone than to weariness in welldoing. Hence it is, that though many are found ready enough to help their brethren, yet the virtue of constancy is so rare, that a large portion soon relax as though their warmth had cooled. But what ought constantly to stimulate us is even this one expression used by the apostle, that the love shown to the saints is shown towards the name of the Lord; for he intimates that God holds himself indebted to us for whatever good we do to our neighbors, according to that saying, "What ye have done to one of the least of these, ye have done to me," (Matthew 25:40;) and there is also another, "He that giveth to the poor lendeth to the Lord." (Proverbs 19:17.)

Footnotes

1 - Nothing can exceed the clearness and the truth of the preceding remarks. The word adikos, unrighteousness, is rendered by many, unmerciful or unkind. But the reason for such a meaning is this: There are three kinds, we may say, of righteousness -- that of the law, of love, and of promise. To act according to the law is to be righteous; to comply with what love requires, that is, to be kind and charitable, is to be righteous, and hence almsgiving is called righteousness has often the meaning of faithfulness or mercy. See 1 John 1:9. Therefore the meaning here is, that God is not so unrighteous as not to fulfill his promise. Hence the notion of merit is at once shown to be groundless. -- Ed

2 - See [25]Appendix X.

For God is not unrighteous - God will do no wrong. He will not forget or fail to reward the endeavors of his people to promote his glory, and to do good. The meaning here is, that by their kindness in ministering to the wants of the saints, they had given full evidence of true piety. If God should forget that, it would be "unrighteous:
(1) because there was a propriety that it should be remembered; and,
(2) because it is expressly promised that it shall not fail of reward; Matthew 10:42.
Your work - Particularly in ministering to the wants of the saints.
Labour of love - Deeds of benevolence when there was no hope of recompense, or when love was the motive in doing it.
Which ye have showed toward his name - Toward him - for the word "name" is often used to denote the person himself. They had showed that they loved God by their kindness to his people; Matthew 25:40, "Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me.
In that ye have ministered to the saints - You have supplied their wants. This may refer either to the fact that they contributed to supply the wants of the poor members of the church (compare the note on Galatians 2:10), or it may refer to some special acts of kindness which they had shown to suffering and persecuted Christians. It is not possible now to know to what particular acts the apostle refers. We may learn.
(1) that to show kindness to Christians, because they are Christians, is an important evidence of piety.
(2) it will in no case be unrewarded. God is not "unjust;" and he will remember an act of kindness shown to his people - even though it be nothing but giving a cup of cold water.

God is not unrighteous - God is only bound to men by his own promise: this promise he is not obliged to make; but, when once made, his righteousness or justice requires him to keep it; therefore, whatever he has promised he will certainly perform. But he has promised to reward every good work and labor of love, and he will surely reward yours; God's promise is God's debt.
Every good work must spring from faith in the name, being, and goodness of God; and every work that is truly good must have love for its motive, as it has God for its end.
The word του κοπου, labor, prefixed to love, is wanting in almost every MS. and version of importance. Griesbach has left it out of the text.
Ministered to the saints - Have contributed to the support and comfort of the poor Christians who were suffering persecution in Judea. As they had thus ministered, and were still ministering, they gave full proof that they had a common cause with the others; and this was one of the things that proved them to be in a state of salvation.

(5) For God [is] not unrighteous to forget your work and labour of love, which ye have shewed toward his name, in that ye have ministered to the saints, and do minister.
(5) He praises them for their charity, by this encouraging them to go forward, and to hold out to the end.

For God is not unrighteous,.... He is just and true, righteous in all his ways and works; there is no unrighteousness nor unfaithfulness in him; and this the apostle makes a reason of his strong persuasion of better things concerning the believing Hebrews; because he was well satisfied of the good work upon them, and he was assured that God was not unrighteous and unfaithful:
to forget your work: which is not to be understood of any good work done by them, for these are generally expressed in the plural number; and besides, these, if at all, are designed in the next clause; moreover, external good works, or such as appear to men to be so, are performed by hypocrites; nor can they be said to be better things, at least, not such as men are saved by: men may fall from these; and supposing them intended, the merit of works cannot be established, as is attempted from hence by the Papists; for the apostle could only consider them as fruits, not as causes of salvation; they are imperfect, and cannot justify, and therefore cannot save; they do not go before to procure salvation, but follow after, and, at most, but accompany; and though God does remember and not forget them, this is owing to his grace, and not to their merit; God's righteousness in remembering them regards not a debt of justice, but a point of faithfulness: but this is to be understood of the work of God upon them, called in Scripture a good work, and the work of faith; and is elsewhere joined, as here, with the labour of love; see 1-Thessalonians 1:3 and this might be called their work, not because wrought by them, but because it was wrought in them; and the grace that came along with it was exercised by them: now from hence the apostle might be persuaded of better things of them, even such as accompany salvation; since this work is a fruit of everlasting and unchangeable love, and is itself immortal, and the beginning of eternal life; and particularly faith is the effect of electing grace; shall never fail; is the means of the saints' preservation; and is connected with everlasting salvation: it follows,
and labour of love, which ye have showed toward his name; the word "labour" is omitted in the Alexandrian copy, Vulgate Latin, Syriac, and Ethiopic versions: this may be understood either of love to God, the name of God being put for himself; who is to be loved for his own sake, on account of the perfections of his nature, as well as for the works of his hands; and which is to be showed for the sake of glorifying him: and this love is laborious; it sets a man to work for God; nor are any works to be regarded but what spring from love to God, and to his name; and from hence the apostle might entertain a good hope of these persons, since their love to God was an effect of God's love to them, is a part of the work of grace, and cannot be lost; all things work together for good to such as love God; and these have a crown of life promised unto them: or else it may be understood of love to the saints, as follows,
in that ye have ministered to the saints, and do minister; in seeking both their temporal and spiritual good; and though all men in general are to be loved, yet especially the saints, who are set apart by God, whose sins are expiated by Christ, and who are sanctified by the Spirit; and love to them being laborious, and appearing in many instances, and this shown for the Lord's sake, for his name's sake, might lead the apostle more strongly to conclude better things of them, even things of a saving nature; since charity or love to the saints is better than gifts, and is the evidence of grace, of passing from death to life, and of being the disciples of Christ; see 1-Corinthians 13:1.

not unrighteous--not unfaithful to His own gracious promise. Not that we have any inherent right to claim reward; for (1) a servant has no merit, as he only does that which is his bounden duty; (2) our best performances bear no proportion to what we leave undone; (3) all strength comes from God; but God has promised of His own grace to reward the good works of His people (already accepted through faith in Christ); it is His promise, not our merits, which would make it unrighteous were He not to reward His people's works. God will be no man's debtor.
your work--your whole Christian life of active obedience.
labour of love--The oldest manuscripts omit "labor of," which probably crept in from 1-Thessalonians 1:3. As "love" occurs here, so "hope," Hebrews 6:11, "faith," Hebrews 6:12; as in 1-Corinthians 13:13 : the Pauline triad. By their love he sharpens their hope and faith.
ye have showed--(Compare Hebrews 10:32-34).
toward his name--Your acts of love to the saints were done for His name's sake. The distressed condition of the Palestinian Christians appears from the collection for them. Though receiving bounty from other churches, and therefore not able to minister much by pecuniary help, yet those somewhat better off could minister to the greatest sufferers in their Church in various other ways (compare 2-Timothy 1:18). Paul, as elsewhere, gives them the utmost credit for their graces, while delicately hinting the need of perseverance, a lack of which had probably somewhat begun to show itself.

For - Ye give plain proof of your faith and love, which the righteous God will surely reward.