Little children, love one another
A story of John that fits his epistles well.
When the holy Evangelist John had lived to extreme old age in Ephesus, he could be carried only with difficulty by the hands of the disciples, and as he was not able to pronounce more words, he was accustomed to say at every assembly, "Little children, love one another."
At length the disciples and brethren who were present became tired of hearing always the same thing and said: "Master, why do you always say this?" Thereupon John gave an answer worthy of himself: "Because this is the commandment of the Lord, and if it is observed then is it enough."
-In Jerome's Commentary on Galatians, cited in Period I, § 3(b) of A Source Book for Ancient Church History, by Joseph Cullen Ayer, Jr.