John Calvin Commentary Titus 1:10

"For there are many unruly men, vain talkers and deceivers, specially they of the circumcision," — Titus 1:10 (ASV)

For there are many unruly. After laying down a general rule, which should be observed everywhere, so that Titus may be more attentive in adhering to it, he presents to him the urgent necessity that should motivate him more than anything else. He warns him that he has to deal with many obstinate and incorrigible people, that many are puffed up with vanity and idle talk, and that many are deceivers. Therefore, they should choose, on the other hand, leaders who are qualified and well prepared to oppose them. For if the children of this world, when dangers arise, increase their concern and watchfulness, it would be disgraceful for us to remain careless and inactive when Satan is using his utmost efforts, as if we were in a state of peace.

Unruly instead of disobedient, (inobedientes), which is the rendering in the old translation for the Greek ἀνυπότακτοι, Erasmus translates it (intractabiles) as incorrigible. He means those who cannot endure to be brought to obey and who throw off the yoke of subjection. He applies the term vain talkers not only to the authors of false doctrines but also to those who, addicted to ambitious display, concern themselves with nothing but useless subtleties.

Ματαιολογία (vain talking) is contrasted with useful and solid doctrine. It therefore includes all trivial and frivolous speculations that contain nothing but empty bombast, because they contribute nothing to piety and the fear of God. Such is all the scholastic theology found today in Popery.

Yet he also calls the same people deceivers of minds. It might be thought preferable to view this as relating to a different class of people; but, personally, I think it means the same class, because the teachers of such trifles entice and fascinate people's minds, so that they no longer receive sound doctrine.

Chiefly they who are of the circumcision. He says that these are chiefly from among the Jews, for it is essential that such plagues be known by all. We should not listen to those who plead that we should spare the reputation of any particular individual when the great danger of the whole Church is at stake. And even greater danger was to be feared from that nation, because it claimed superiority over others on account of the sacredness of its lineage. This is therefore the reason Paul reproves the Jews more sharply: to take from them the power to do harm.