Two things are here to be considered, namely, the grace and duty proposed and enforced, and the sin or vice specified and opposed.
Observe, 1. The grace proposed, or the duty recommended, namely, the love of our brother: He that loveth his brother abideth in the light, and there is no occasion of stumbling in him.
Where note, 1. The nature of brotherly love; it is a gracious propensity of heart, which a Christian bears, for Christ's sake, to his neighbour, whereby he wills, and, to his power, procures all good for him; or it is that brotherly affection which every true Christian chiefly bears to all his fellow-members in Christ, for grace sake.
Note, 2. The benefits attending the practice of this grace and duty.
1. His condition is happy, he abideth in the light: that is, he is in a state of grace. Charity is an evident demonstration of sanctity; and accordingly St. Paul, Gal_5:1 reckoning up the fruits of the spirit, placeth love in the front of them.
2. His conversation is holy, there is no occasion of stumbling in him; that is, he walketh inoffensively in a state of grace, and neither stumbleth himself, neither is there occasion given by him that others should stumble, or be drawn into any sin.
Observe, 2. The sin specified, and the vice opposed, namely, hating of our brother: He that hateth his brother is in darkness, and walketh in darkness.
Where note, 1. It is not any hurting, but hating our brother, that is forbidden, and that this hatred is not only forbidden whilst he is our friend, but when he becomes our enemy. To hate a friend is unhuman; to hate an enemy is unchristian. And further, it must be noted, that whatever falls short of the duty of loving, cometh within the compass of hating our brother: from every departure from love is a degree of hatred.
Note, 2. The dismal character given of those persons who hate their brother; they are described by their wicked disposition; they are in darkness: by their vicious conversation; they walk in darkness: by their miserable condition; they know not whither they go, because that darkness hath blinded their eyes.
From the whole learn, That we must love all, in the various measures and degrees, according to which God appeareth in them: That is, we must love all men, as men, above the brutes; and we must love all professed Christians, above all other men; and we must love real Christians, especially such of them as are eminent for wisdom, goodness, and usefulness, above all other Christians. The light of knowledge and the heat of love must be inseparable.