Seeing you have purified your souls in your obedience to the truth through the Spirit in sincere brotherly affection, love one another from the heart fervently:
He calls it unfeigned, (ἀνυπόκριτον), as Paul calls faith in 1 Timothy 1:5; for nothing is more difficult than to love our neighbors in sincerity. For the love of ourselves rules, which is full of hypocrisy; and besides, every one measures his love, which he shews to others, by his own advantage, and not by the rule of doing good. He adds, fervently; for the more slothful we are by nature, the more ought every one to stimulate himself to fervor and earnestness, and that not only once, but more and more daily. 