The son of day clothes himself for the day's work or battle. The same association of ideas as in 1Th 5:6, 1Th 5:8, is found in Rom 13:12-14; Rev 16:15; 1Pe 1:13. Comp. lxx, Bar. 5:2.
Breastplate - helmet
Comp. Eph 6:14. The figures are not original with Paul. See Isa 59:17; Wisd. 5:18, 19. Notice that only defensive armor is mentioned, in accordance with the darkness and uncertainty of the last time; and that the fundamental elements of Christian character, faith, hope, and love, are brought forward again as in 1Th 1:3; 1Co 13:13. For the figure of the armed soldier, comp. also Rom 13:12; 2Co 10:4.