NOTES for Rom 13:13
The apostle's words about the daylight, in which it is better not to behave disgracefully, sometimes make people smile: reading them, one might think that under cover of night one may do what one would not do in the light of day. Meanwhile, Paul speaks of the day in a special, specifically Yahwistic sense. The Day of Yahweh, or, as it is usually called in Russian translations, the Day of the Lord, is a special time in the life of the people of God. It is a time when God directly and immediately intervenes in the people's life.
Times of natural disaster or war, for example, were called the Day of Yahweh. But such intervention was also connected with the idea of God's judgment. Judgment, however, was understood differently at different times. The earliest and simplest idea of it viewed war or natural disaster as punishment for a sin committed by the people.
But even before the Babylonian exile this idea gave way to another: judgment came to be seen as a kind of weighing of a person and his deeds on certain spiritual scales, much as neighboring peoples imagined divine judgment. Among those peoples, however, this judgment was usually postmortem, and the soul of a person appearing for judgment was weighed on the scales. Among the Jews, God weighed human deeds while the person was still alive, determining whether the person was worthy to be left alive or by his deeds had already deserved death.
The Savior speaks of judgment in a completely different way: according to Him, judgment consists in this, that light has come into the world. He clearly means the light of the Kingdom He brought into the world, and now it depends on the person himself whether he accepts this light or runs away because he understands that his life is incompatible with it.
Paul understands the Day of Yahweh in the same way: it is the day when light enters the world. And if before one could still delay making a choice, postpone repentance and conversion, now there is no time left: the decision must be made immediately, and once made, it must be carried out resolutely and unswervingly. Indeed, the issue is salvation, the Kingdom, what determines a person's fate in eternity. Hesitation is out of place here.