Albert Barnes Commentary Psalms 88:1

"O Jehovah, the God of my salvation, I have cried day and night before thee." — Psalms 88:1 (ASV)

O Lord God of my salvation - On whom I depend for salvation; who alone can save me. Luther renders this, “O God, my Saviour.”

I have cried day and night before you - literally, “By day I cried; by night before you;” that is, my prayer is constantly before you. The meaning is, that there was no intermission to his prayers; he prayed all the while.

This does not refer to the general habit of his life, but to the time of his sickness. He had prayed most earnestly and constantly that he might be delivered from sickness and from the dangers of death. He had, until now, obtained no answer, and he now pours out and records a more earnest petition to God.