Adam Clarke on 1 John 3:23

That we should believe on the name of his Son - We are commanded to believe on Christ, that for the sake of his passion and death we may be justified from all things from which we could not be justified by the law of Moses; and being through him redeemed from the guilt of sin, restored to the Divine favor, and made partakers of the Holy Ghost, we are enabled to love one another as he gave us commandment; for without a renewal of the heart, love to God and man is impossible, and this renewal comes by Christ Jesus.