John Calvin Commentary Psalms 118:5

"Out of my distress I called upon Jehovah: Jehovah answered me [and set me] in a large place." — Psalms 118:5 (ASV)

I called upon God in my distress. We have here a particular application of the doctrine we previously mentioned, concerning the person of David. Connected with this is also the rejoicing of the whole Church, for whose public welfare God provided by upholding him. By his own example he strengthens the faithful, showing them that they should not lose heart in the day of adversity.

He seems to intentionally anticipate an objection that is likely to arise in people's minds the moment God's goodness is proclaimed: “Why does He permit His servants to be so severely oppressed and afflicted?” David therefore reminds them, nevertheless, that God’s mercy never fails, for in prayer we have consolation and an antidote for all our troubles. Furthermore, the time when he says he made supplication, and through it obtained deliverance, was one of distress. This is significant for us, teaching that the time of sad adversity is most appropriate for abounding in prayer.