The Apostle Paul
Romans 12:10ESV·traditional attribution

Love one another with brotherly affection. Outdo one another in showing honor.

John Calvin Reformed @genevareformer

10. With brotherly love, etc. By no words could he satisfy himself in setting forth the ardor of that love, with which we ought to embrace one another: for he calls it brotherly, and its emotion στοργὴν, affection, which, among the Latins, is the mutual affection which exists between relatives; and truly such ought to be that which we should have towards the children of God.

Matthew Henry Presbyterian @wholebiblehenry

We may observe here, according to the scheme mentioned in the contents, the apostle's exhortations, I. Concerning our duty to God, We see what is godliness. 1. It is to surrender ourselves to God, and so to lay a good foundation. We must first give our own selves unto the Lord, Co2 8:5. This is here pressed as the spring of all duty and obedience, Rom 12:1, Rom 12:2.

Commenting on Romans 12:1-21

John Gill Reformed Baptist @doctorgill

Be kindly affectioned one to another with brotherly love,.... This is one branch of that love, before advised to, which should be unfeigned, and without guile and deceit. The objects of this grace are "brethren", not in such sense as all the descendants of Adam are, or men of the same country be, or as such who are born of the same parents in a...