Lit., out of the death. The article marks it as one of the two spheres in which men must be; death or life. The death, the life, present one of those sharp oppositions which are characteristic of the Epistle; as love, hatred; darkness, light; truth, a lie. Ὁ θάνατος the death, occurs in John's Epistles only here and in the next clause. In the Gospel, only Joh 5:24. Personified in Rev 1:18; Rev 6:8; Rev 9:6; Rev 20:13.
Unto life (εἰς τὴν ζωήν)
Rev., better, into. Compare enter into the life, Mat 28:8; Mat 19:17.
Because
The sign of having passed into life; not the ground.
We love the brethren (ἀγαπῶμεν του,ς ἀδελφούς)
The only occurrence of the phrase. Elsewhere, love one another, or love his brother. See on 1Jo 2:9.