'Day and Night' in the Bible

Let your ear now be attentive, and your eyes open, that you may listen to the prayer of your servant, which I pray before you at this time, day and night, for the children of Israel your servants while I confess the sins of the children of Israel, which we have sinned against you. Yes, I and my father's house have sinned.

But we made our prayer to our God, and set a watch against them day and night, because of them.