Are we not all one another's brothers?

Patristic reading
How much greater should then be our compassion for brothers and fellow believers!

Are we not all one another's brothers? Are we not of one blood? Are we not of the same dust? (cf. Gen 2:7) Is not someone who sees a beast of burden being carried over a precipice seized with pity? How much more then for brothers and fellow believers! Hence the blessed Apostle wept for the enemies of the Cross of Christ (Phil 3:18), praying with unremitting grief of heart (cf. Rom 92) . Hence the Prophet Jeremy lamented over Israel and left behind various lamentations in writing (cf. Lam 1:1). Hence the great Moses cried to God: If you will forgive them their sin, forgive; if not, wipe me out of your book of life (Ex 32:32). And indeed each of the saints had the same sympathy and made entreaty for the others. Should not we then, if want to walk in their footsteps, not simply have in view what concerns ourselves, but also pray on behalf of the world, having mercy and pity for those who are living in the distraction of life, those who are in the grip of heresies, those who have been led away into error, those in the darkness of paganism, in brief all mankind, according to what we have been commanded by the Apostle to make supplications and prayers (cf. 1Tim 2:1). For thus we shall profit ourselves before the rest, being filled with compunction and cleansed of passionate habits.

Theodore the Studite, Small Catecheses 52