From the early Church Fathers to now.
3 Patristic · 1 Orthodox · 1 Catholic
“Let the charity of the brotherhood abide in you.”
“See how he enjoins them to preserve what they had: he does not add other things. He did not say, "Be loving as brethren," but, "Let brotherly love continue." And again, he did not say, "Be hospitable," as if they were not, but, "Be not forgetful of hospitality," for this was likely to happen owing to their afflictions.”
“Behold, the Lord was not recognized while He was speaking, and He deigned to be recognized while He was being fed. Therefore, dearest brothers, love hospitality, love the works of charity. For hence it is said through Paul: "Let brotherly love continue in you, and do not forget hospitality. For through this some have pleased, having received angels as guests." Hence Peter says: "Be hospitable to one another without murmuring." Hence Truth itself says: "I was a stranger, and you took me in."”
“He did not say that you have acquired brotherly love and hospitality, for they had these, as it seemed; but since they were in danger, due to unceasing afflictions, of abandoning the care of these virtues, he says: "Let brotherly love... continue," let it be firm, and do not allow yourselves to avoid it.”
“Having instructed them how to bear with evil, the Apostle now tells them how to act in doing good. Hence, according to a Gloss he is beginning his moral instruction after commending and urging them to imitate him. In regard to this he does two things: first, he urges them to good; secondly, he prays for them (v. 20). In regard to the first he does three things: first, he shows them how to do good to their neighbor; secondly, to themselves (v. 4); thirdly, to prelates (v. 7). He says, therefore: Thus, we have said that an immovable kingdom has been promised to us. If we would enter it, we must have charity: Let brotherly love continue: 'He that does not love his brother whom he sees, how can he love God whom he does not see' (1 Jn. 4:20); 'Honor one another; love the brotherhood' (1 Pt 2:17). But because charity is not idle, as Gregory says, he urges them to acts of charity: 'Let us love not in tongue but in deed and in truth' (1 Jn. 3:18). Hence, he says that we should show charity to travelers by hospitality, to those in bands by compassion, to the poor by coming to their aid. In regard to the first he says, do not neglect to show hospitality to strangers.”
“"Let brotherly love continue." Let it be unwavering, do not allow it to escape from you.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.