Joseph Benson's Commentary of the Old and New Testaments - 1 John 3:3
1 John 3:3. And every man that hath this hope in him An expectation of seeing Christ as he is, built on a solid foundation, namely, the foundation of being a child and heir of God; purifieth himself By applying to, and confiding in, the purifying blood of Christ, with a penitent, believing heart; by earnestly praying for and receiving the purifying Spirit of God; by obeying the purifying word, (1 Peter 1:22,) and by exercising purifying faith in the truths and promises of the gospel, Acts... read more
Albert Barnes' Notes on the Whole Bible - 1 John 3:4
Whosoever committeth sin transgresseth also the law - The law of God given to man as a rule of life. The object of the apostle here is to excite them to holiness, and to deter them from committing sin, perhaps in view of the fact stated in 1 John 3:3, that everyone who has the hope of heaven will aim to be holy like the Saviour. To confirm this, he shows them that, as a matter of fact, those who are born of God do lead lives of obedience, 1 John 3:5-10; and this he introduces by showing what is... read more