Charles H. Spurgeon on Psalms 119:148

"Mine eyes prevent the night watches." The Hebrew word means a watch a part of the night, so called from military watches, or a dividing of the night to keep guard. The idea of the Psalmist here is, that he anticipated these regular divisions of the night in order that he might engage in devotion. Instead of waiting for their return, he arose for prayer before they recurred; so much did his heart delight in the service of God. The language would seem to be that of one who was accustomed to pray in these successive "watches" of the night; the early, the middle, and the dawn. This may illustrate what occurs in the life of all who love God. They will have regular seasons of devotion, but they will often anticipate those seasons. They will be in a state of mind which prompts them to pray; when nothing will meet their state of mind but prayer; and when they cannot wait for the regular and ordinary season of devotion; like a hungry man, who cannot wait for the usual and regular hour of his meals. The meaning of the phrase, "Mine eyes prevent, "is that he awoke before the usual time for devotion. Albert Barnes.