Also unto thee, O Lord, belongeth mercy - Power, indeed, belongs to God Psalm 62:11; but this is an attribute to be feared, and while, in one respect, it will inspire confidence, or while it gives us the assurance that God is able to defend us when all else shall fail, yet, unattended by any other attribute, it might produce only apprehension and alarm. What man, weak and sinful man, needs to know is not merely that God has almighty power, but how that power will be wielded, or with what other attributes it is combined; whether it will be put forth to destroy or to save; to kill or to keep alive; to crush or to uphold. Man, therefore, needs the assurance that God is a benevolent Being, as really as that he is a powerful Being; that he is disposed to show mercy; that his power will be put forth in behalf of those who confide in him, and not employed against them. Hence, the attribute of mercy is so essential to a proper conception of God; and hence, the psalm so appropriately closes by a reference to his mercy and compassion.
For thou renderest to every man according to his work - As this stands in our version, it would seem that the psalmist regarded what is here referred to as a manifestation of mercy. Yet the "rendering to every man according to his work" is an act of justice rather than of mercy. It is probable, therefore, that the word rendered "for" - כי kı̂y - does not refer here to either of the attributes mentioned exclusively - either power or mercy - but is to be understood with reference to the general course of argument in the psalm, as adapted to lead to confidence in God. The fact that he is a God who will deal impartially with mankind, or who will regard what is right and proper to be done in view of the characters of mankind, is a reason why they should confide in God - since there could be no just ground of confidence in a Being who is not thus impartial and just. All these combined - power, mercy, equity - constitute a reason why people should confide in God. If either of these were missing in the divine character, man could have no confidence in God. If these things do exist in God, unlimited confidence may be placed in him as having all needful power to save; as being so merciful that sinful people may trust in him; and as being so just and equal in his dealings that all may feel that it is right to repose confidence in a Being by whom all the interests of the universe will be secured. Compare 1-John 1:9.

Also unto thee, O Lord, [belongeth] mercy: for thou (k) renderest to every man according to his work.
(k) So that the wicked will feel your power, and the godly your mercy.

Also unto thee, O Lord, belongeth mercy,.... This is the other thing the psalmist had heard, and was assured of, and which encouraged his hope and trust in the Lord; that mercy belonged to him, Psalm 130:7; as appears, not only from the common bounties of his providence, daily bestowed upon his creatures; but from the special gift of his Son, and of all spiritual mercies and blessings in him; from the regeneration of the Lord's people, the pardon of their sins, and their eternal salvation;
for thou renderest to every man according to his work; and which is a reason proving that both power and mercy belong to God; power in punishing the wicked according to their deserts, and mercy in rewarding the saints, not in a way of merit, or of debt, but of grace. Some interpret the words, as Aben Ezra and Kimchi observe, "though thou renderest", &c. that is, God is gracious and merciful, though he is also just and righteous in rendering to every man as his work is, whether it be good or evil.

for thou renderest--literally, "that Thou renderest," &c., connected with "I heard this," as the phrase--"that power," &c. [Psalm 62:11] --teaching that by His power He can show both mercy and justice.

Therefore - God is almighty, therefore he can easily destroy all his enemies: he is also merciful, and therefore will pardon good mens failings. Renderest - And this as he is obliged to do by his holy nature, so is he able to do it, being omnipotent, and willing to do it to the godly (which was the only thing that might be doubted, because of their manifold miscarriages) because he is merciful and gracious.