John Calvin Commentary Psalms 42:9

"I will say unto God my rock, Why hast thou forgotten me? Why go I mourning because of the oppression of the enemy?" — Psalms 42:9 (ASV)

Concerning I will say to God my rock: If we read the preceding verse in the past tense, the meaning of this verse will be: Since God has, in this way, until now shown Himself so kind toward me, I will pray to Him now with so much greater confidence, for the experience I have had of His goodness will inspire me with courage.

But if the preceding verse is rendered in the future tense, David, in this verse, combines the prayer it contains with the reflections that faith led him to make. And surely, whoever, from a persuasion of the paternal love of God, anticipates for himself the same favor that David has just described, will also be led by his example to pray for it with greater confidence.

The meaning, then, will be this: Since I expect that God will be favorable to me, inasmuch as by day He manifests His favor toward me and continues to do this, so that even by night I have occasion to praise Him, I will bewail my miseries more frankly before Him, saying, O Lord! my rock, why hast thou forgotten me? In making such a complaint, the faithful are not to be understood as meaning that God has utterly rejected them, for if they did not believe that they were under His care and protection, it would be in vain for them to call upon Him.

But they speak in this manner according to the flesh. This forgetfulness, then, relates both to outward appearance and to the anxiety by which the faithful are troubled according to the flesh, although, meanwhile, they rest assured by faith that God regards them and will not be deaf to their request.