1 Thessalonians 5:4-7

But ye, brethren, are not in darkness, that that day should overtake you as a thief. Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness. Therefore let us not sleep, as do others; but let us watch and be sober. For they that sleep, sleep in the night; and they that be drunken are drunken in the night.