Calvin's Commentaries, Vol. 43: Timothy, Titus, and Philemon, tr. by John King, [1847-50], at sacred-texts.com
Paul, having only laid the foundations of the church in Crete, and hastening to go to another place, (for he was not the pastor of a single island only, but the Apostle of the Gentiles,) had given charge to Titus to prosecute this work as an Evangelist. It is evident from this Epistle that, immediately after Paul’s departure, Satan labored not only to overthrow the government of the Church, but likewise to corrupt its doctrine.
There were some who, through ambitious motives, wished to be elevated to the rank of pastors, and who, because Titus did not comply with their wicked desires, spoke unfavorably of him to many persons. On the other hand, there were Jews who, under the pretense of supporting the Mosaic law, introduced a great number of trifles; and such persons were listened to with eagerness and with much acceptance. Paul therefore writes with this design, to arm Titus with his authority, that he may be able to bear so great a burden; for undoubtedly there were some who fearlessly despised him as being but one of the ordinary rank of pastors. It is also possible that complaints about him were in circulation, to the effect that he assumed more authority than belonged to him when he did not admit pastors till he had made trial and ascertained their fitness.
Hence we may infer, that this was not so much a private epistle of Paul to Titus, as it was a public epistle to the Cretans. It is not probable that Titus is blamed for having with too great indulgence raised unworthy persons to the office of bishop, or that, as an ignorant man and a novice, he is told what is that kind of doctrine in which he ought to instruct the people; but because due honor was not rendered to him, Paul clothes him with his own authority, both in ordaining ministers and in the whole government of the Church. Because there were many who foolishly desired to have another form of doctrine than that which he delivered, Paul approves of this alone — rejecting all others — and exhorts him to proceed as he had begun.
First, then, he shows what sort of persons ought to be chosen for being ministers. 208 Among other qualifications, he requires that a minister shall be well instructed in sound doctrine, that by means of it he may resist adversaries. Here he takes occasion to censure some vices of the Cretans, but especially rebukes the Jews, who made some kind of holiness to consist in a distinction of food, and in other outward ceremonies. In order to refute their fooleries, he contrasts with them the true exercises of piety and Christian life; and, with the view of pressing them more closely, he describes what are the duties which belong to every one in his calling. These duties he enjoins Titus diligently and constantly to inculcate. On the other hand, he admonishes others not to be weary of hearing them, and shows that this is the design of the redemption and salvation obtained through Christ. If any obstinate person oppose, or refuse to obey, he bids him set that person aside. We now see that Paul has no other object in view than to support the cause of Titus, and to stretch out the hand to assist him in performing the work of the Lord.
“Pour estre ministres et pasteurs de l’Eglise.” — “To be ministers and pastors of the Church.”