John Calvin Commentary Psalms 74:21

"Oh let not the oppressed return ashamed: Let the poor and needy praise thy name." — Psalms 74:21 (ASV)

Let not him who is oppressed return with shame. The word return, when referring to God, is equivalent to the expression, to go away empty. The faithful, then, implore Him that they might not be shamed by suffering rejection from Him. They call themselves afflicted, poor, and needy, as a plea to obtain Divine favor and mercy.

However, it should be noted that they do not speak insincerely or exaggerate their distresses, but rather indicate that through so many calamities they had been brought to such a desperate state that no source of help in the world remained for them. This example teaches us that when we are reduced to the greatest extremity, a remedy for our misery is always ready in calling upon God.