John Gill Bible Commentary

Mine eyes prevent the night watches,.... The Targum is, "the morning and evening watches.'' There were three of them; Kimchi interprets it of the second and third; the meaning is, that the psalmist was awake and employed in one religious exercise or another, praying, reading, or meditating; either before the watches were set, or however before the time that some of them took place, or at least before they were all over; that I might meditate in thy word; he rose so early, in order to give himself up to meditation on the word of God; that he might be better instructed in the knowledge of divine things; that he might have solace and comfort from thence under his afflictions; and that he might be better furnished for the work of prayer; for the more familiar the word of God is to us, the better able we are to speak to God in his own language.