John Calvin Commentary Psalms 42:11

"Why art thou cast down, O my soul? And why art thou disquieted within me? Hope thou in God; for I shall yet praise him, [Who is] the help of my countenance, and my God." — Psalms 42:11 (ASV)

O my soul! why are you cast down? This repetition shows us that David had not so completely overcome his temptations in one encounter, or by one extraordinary effort, as to make it unnecessary for him to enter anew into the same conflict. By this example, therefore, we are admonished that although Satan, by his assaults, often subjects us to a renewal of the same trouble, we should not lose our courage or allow ourselves to be cast down.

The latter part of this verse differs from the fifth verse in one word, while in every other respect they agree. In the fifth verse, it is the helps of His countenance, but here we have the relative pronoun of the first person, thus, The helps of My countenance. Perhaps in this place, the letter w, vau, which in the Hebrew language denotes the third person, is missing. Still, as all the other versions agree in the reading I have adopted, David might, without any absurdity, call God by this designation, The helps or salvations of My countenance, since he looked with confidence for a clear and certain deliverance, as if God were to appear visibly as his defender and the protector of his welfare. There can, however, be no doubt that in this place the term helps or salvations is to be viewed as an epithet applied to God, for immediately after it follows, and my God.