And every man that hath this hope in him purifieth himself, even as he is pure.
This hope - of being hereafter "like Him." Answering to "we know" (1 John 3:2); so far from it being a vague, uncertain hope. Faith, love, and hope, concur (1 John 3:11; 1 John 3:23). In, х epi (G1909)] - 'resting upon Him:' on His promises.
Purifieth himself - by Christ's Spirit in him (John 15:3; John 15:5, end). One's justification through faith is presupposed (Acts 15:9).
As he is pure, х hagnos (G53)] - unsullied with uncleanness. The Second Person, by whom both the Law and Gospel were given.
Sin is incompatible with birth from God (1 John 3:1-3). John often sets forth the truth negatively, which he before set forth positively. He had shown birth from God involves self-purification; he now shows where sin - i:e., absence of self-purification-is, there is no birth from God.