O Lord God of my salvation - On whom I depend for salvation; who alone canst save me. Luther renders this, “O God, my Saviour.”
I have cried day and night before thee - literally, “By day I cried; by night before thee;” that is, my prayer is constantly before thee. 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, as yet, obtained no answer, and he now pours out, and records, a more earnest petition to God.