John Calvin Commentary Psalms 16:7

"I will bless Jehovah, who hath given me counsel; Yea, my heart instructeth me in the night seasons." — Psalms 16:7 (ASV)

Finally, David confesses that it was entirely due to the pure grace of God that he had come to possess such a great good, and that he had been enabled to partake of it by faith. It would be of no advantage to us for God to offer Himself freely and graciously to us if we did not receive Him by faith, since He invites both the reprobate and the elect to Himself in common; but the former, by their ingratitude, deprive themselves of this inestimable blessing.

Therefore, let us understand that both these things come from the free generosity of God: first, His being our inheritance, and next, our coming to possess Him by faith. The counsel that David mentions is the inward illumination of the Holy Spirit, by which we are kept from rejecting the salvation to which He calls us—something we would otherwise certainly do, considering the blindness of our flesh.

From this we gather that those who attribute the choice of accepting or rejecting God's grace to human free will shamefully distort that grace and display as much ignorance as impiety. That this teaching of David should not be understood as external instruction is clear from his words, for he tells us that he was instructed in the night when he was secluded from human sight.

Again, when he speaks of this being done in his reins, he undoubtedly means secret inspirations. Furthermore, it should be carefully noted that, in speaking of the time when he was instructed, he uses the plural, saying it was done in the nights. By speaking this way, he not only attributes the beginning of faith to God but also acknowledges that he is continually progressing under His guidance. Indeed, it is necessary for God, throughout our entire lives, to continue to correct the vanity of our minds, to kindle the light of faith into a brighter flame, and by every means to advance us further in acquiring spiritual wisdom.