1 sn The day of the Lord is the period of time in the future when the Lord will intervene in the events of this earth to consummate his redemption and his judgment (Isa 2:11-12; 13:6-13; Ezek 30:3; Joel 1:15; 2:32; 3:18; Amos 5:18-20; Obad 15-17; Zeph 1:7-18; 2:2-3; Zech 14:1, 13, 20-21; Mal 4:1, 5; 1 Cor 1:8; 5:5; 2 Cor 1:14; 2 Thess 2:2; 2 Pet 3:10). It includes both blessings and curses, though the latter is emphasized here.
2 sn Jesus used a thief coming at night as an illustration of the unexpected and hostile nature of the coming of God’s judgment in the future. This is repeated in various ways in v. 4; 2 Pet 3:10; Rev 3:3; 16:15.
3 tc ‡ δέ (de, “now”) is found in א2 B D 0226 6 1505 1739 1881 al, but lacking in א* A F G 33 it. γάρ (gar, “for”) is the reading of the Byzantine text and a few other witnesses (Ψ 0278 Ï). Although normally the shorter reading is to be preferred, the external evidence is superior for δέ (being found in the somewhat better Alexandrian and Western witnesses). What, then, is to explain the γάρ? Scribes were prone to replace δέ with γάρ, especially in sentences suggesting a causal or explanatory idea, thus making the point more explicit. Internally, the omission of δέ looks unintentional, a case of homoioarcton (otandelegwsin). Although a decision is difficult, in this instance δέ has the best credentials for authenticity.
4 tn Grk “peace and security,” with “there is” understood in the Greek construction.
5 tn Grk a singular “birth pain.”
6 tn Grk “brothers.” See note on the phrase “brothers and sisters” in 1:4.