By this we know that we are the children God,.... The Ethiopic version reads, "by this know that we love God"; which, in connection with what follows, makes a tautology, and is a proving "idem per idem": whereas the apostle's view is to show when love to the saints is right; and that is, when we love God, and keep his commandments: love to the brethren may arise from such a cause, as may show that it is not brotherly love, or of a spiritual kind; it may arise from natural relation, or civil friendship, or from a benefit or favour received from them, and from some natural external excellency seen in them; and a man may do acts of love and kindness to the brethren, from what may be called good nature in himself, or with sinister views; but true love to the brethren springs from love to God: such who love the saints aright, and by which they may know they do so, they love them because they themselves love God, and in obedience to his command; they love them because they belong to God, and are the objects of his love; because his grace is wrought in them, and his image stamped upon them.