1 Thessalonians 5:8

But let us, since we are of the day, be sober, putting on the breastplate of faith and love; and for a helmet, the hope of salvation. [The idea that the thief comes in the night as set forth in verse 2 suggests the thought that those that live in the night must find it hard to guard against him. But those who live in a perpetual day are not easily surprised by a thief. Now, the Christians, being enlightened as to the Lord's coming, lived in such a perpetual day; in fact, to use a Hebraism, they were "sons" of the light and of the day; i. e., they belonged to the day. There was no need, therefore, that their spiritual faculties should be asleep. Day is no time for such sleep, and those that dwelt in it should find it easy to watch and be sober and wear their armor as good soldiers, while those who dwelt in the night would find it hard to keep awake, to keep sober, or to wear armor. It was common in the East for people to be drunken in the night-time, as they were ashamed to be seen intoxicated in the daylight (Acts 2:15). The nights of the Greeks and Romans were given to revelry, and it was counted an especial mark of profligacy to be drunken in the daytime (2 Peter 2:13). Polybius emphasized the abandoned condition of a drunkard by saying, "Even by day he was often conspicuous to his friends, drunk."]