Be kindly affectioned one to another with brotherly love; in honour preferring one another;

People's New Testament

12:10 With brotherly love. The brotherhood of the saints was not a name only, but a real tie of tenderness and love; and each, in the spirit of true brotherhood, was to seek the honor of his Christian brother.

Wesley's Notes

12:10 In honour preferring one another - Which you will do, if you habitually consider what is good in others, and what is evil in yourselves.

King James Translators' Notes

with...: or, in the love of the brethren

Jamieson-Fausset-Brown Bible Commentary

10. Be, &c.-better, "In brotherly love be affectionate one to another; in [giving, or showing] honor, outdoing each other." The word rendered "prefer" means rather "to go before," "take the lead," that is, "show an example." How opposite is this to the reigning morality of the heathen world! and though Christianity has so changed the spirit of society, that a certain beautiful disinterestedness and self-sacrifice shines in the character of not a few who are but partially, if at all under the transforming power of the Gospel, it is only those whom "the love of Christ constrains to live not unto themselves," who are capable of thoroughly acting in the spirit of this precept.

Matthew Henry's Concise Commentary

12:9-16 The professed love of Christians to each other should be sincere, free from deceit, and unmeaning and deceitful compliments. Depending on Divine grace, they must detest and dread all evil, and love and delight in whatever is kind and useful. We must not only do that which is good, but we must cleave to it. All our duty towards one another is summed up in one word, love. This denotes the love of parents to their children; which is more tender and natural than any other; unforced, unconstrained. And love to God and man, with zeal for the gospel, will make the wise Christian diligent in all his wordly business, and in gaining superior skill. God must be served with the spirit, under the influences of the Holy Spirit. He is honoured by our hope and trust in him, especially when we rejoice in that hope. He is served, not only by working for him, but by sitting still quietly, when he calls us to suffer. Patience for God's sake, is true piety. Those that rejoice in hope, are likely to be patient in tribulation. We should not be cold in the duty of prayer, nor soon weary of it. Not only must there be kindness to friends and brethren, but Christians must not harbour anger against enemies. It is but mock love, which rests in words of kindness, while our brethren need real supplies, and it is in our power to furnish them. Be ready to entertain those who do good: as there is occasion, we must welcome strangers. Bless, and curse not. It means thorough good will; not, bless them when at prayer, and curse them at other times; but bless them always, and curse not at all. True Christian love will make us take part in the sorrows and joys of each other. Labour as much as you can to agree in the same spiritual truths; and when you come short of that, yet agree in affection. Look upon worldly pomp and dignity with holy contempt. Do not mind it; be not in love with it. Be reconciled to the place God in his providence puts you in, whatever it be. Nothing is below us, but sin. We shall never find in our hearts to condescend to others, while we indulge conceit of ourselves; therefore that must be mortified.