John Chrysostom

The example again is as before, and the gain unspeakable. For this is a thing that doth God especial glory, the being closely united. And so if even against thy will and for His sake, thou be at variance with thy brother, consider that by putting an end to thine anger thou art glorifying thy Master, and if not on thy brother's account, for this at all events be reconciled to him: or rather for this first. …

Homily on Romans 27 ↗

Theophylact of Ohrid

He repeats the previous exhortation and brings Christ as an example, so that we would accept one another, because this serves to the glory of God. For our unity above all glorifies God, as it is said: "the world will believe that You sent Me," if the disciples "are one" (Jn. 17:21-23). On the contrary, disagreements bring dishonor to God. For when the pagans see that Christians disagree among themselves, they blame the faith itself.

Commentary on Romans ↗

Thomas Aquinas

Then when he says, wherefore, receive one another, he clarifies the first part of the admonition in which he had said that the stronger should bear with the failings of the weak. In regard to this he does three things: first, he resumes the admonition; second, he presents a reason from the example of Christ, at as Christ also; third, he adds a reason, at now may the God of hope. …

Commentary on Romans ↗