en_tn/1th/05/04.md

you, brothers

Here "brothers" means fellow Christians.

are not in darkness

Paul speaks of evil and ignorance about God as if they were darkness. AT: "you are not unknowing, like people who live in the dark" (See: rc://en/ta/man/translate/figs-metaphor)

so that the day would overtake you like a thief

The day when the Lord comes should not be a surprise to believers. (See: rc://en/ta/man/translate/figs-simile)