He sends the disciples to preach two and two, because there are two commands of charity, the love of God, and love of our neighbour; (and charity cannot exist without at least two;) thereby silently suggesting to us, that he who has not love to another, ought not to undertake the office of preaching.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. 17. in Ev.