John Chrysostom

"And shun profane novelties of speech." For they will not stop there. For when anything new has been introduced, it is ever producing innovations, and the error of him who has once left the safe harbor is infinite, and never stops. "For they will increase unto more ungodliness," he says, "And their word will eat as doth a canker." It is an evil not to be restrained, not curable by any medicine, it destroys the whole frame. He shows that novelty of doctrine is a disease, and worse than a disease. …

Homily on 2 Timothy 5 ↗

Theophylact of Ohrid

That is, flee. Saint John Chrysostom everywhere gives us to understand by "empty talk" – κενοφωνία – new currents – καινοτομίας in teaching and in those who follow it. Some, however, instead of "avoid" – περιίστασο read: περισσωσίστασο – pay more attention to stopping and restraining them. This is not so. An incorrigible evil, he says, one that admits of no remedy: it infects everything, and people are incorrigible.

Commentary on 2 Timothy ↗

Oecumenius

Avoid profane and empty chatter. If anything new in the preaching has been introduced from more recent empty chatter, it is altogether wicked and profane. As for that, either remove it or stand firmly to stop and prevent it altogether. for they will increase in ungodliness. For if anything spurious is introduced, Paul says, it always leads to absurdity. And he receives a greater offering every day.

Commentary On 2 Timothy ↗

Thomas Aquinas

Shun profane and vain babblings. Here he shows two things to avoid, namely, profane and vain babblings. These might refer to the same thing or to different things: for profane things are those which are far from the fane, i.e., far from divine worship. These are the sayings of heretics and must be avoided; hence, he says: shun profane things. But these profane things can also refer to statements contrary to the faith, and as such, are vain babblings and myths: they have spoken vain things, everyone to his neighbor (Ps 11:3). …

Commentary on 2 Timothy ↗