ISB ~ 1 Thessalonians 3 v13

holiness:Moral and spiritual sanctity. See note on 1 Thess 4:3.

the coming:The third mention of Christ’s return so far in the letter (1:10; 2:19). See note on 1 Thess 2:19.

all his saints:Or, “all his holy ones”. This could refer to the blessed angels or the victorious saints or both. Most likely, Paul is saying that Christ will descend from heaven with an army of holy angels. This is the picture drawn by Jesus (Mk 8:38), by the OT (Zech 14:5), and by Paul himself in his follow-up letter (2 Thess 1:7).