Isaiah 28:11

These gifts were first bestowed on us the apostles when we were about to preach the Gospel to every creature, and afterwards were of necessity afforded to those who had by our means believed; not for the advantage of those who perform them, but for the conviction of the unbelievers, that those whom the word did not persuade, the power of signs might put to shame: for signs are not for us who believe, but for the unbelievers, both for the Jews and Gentiles. For neither is it any profit to us to cast out demons, but to those who are so cleansed by the power of the Lord; as the Lord Himself somewhere instructs us, and shows, saying: "Rejoice not because the spirits are subject unto you; but rejoice, because your names are written in heaven." [Luke 10:20] Since the former is done by His power, but this by our good disposition and diligence, yet (it is manifest) by His assistance. It is not therefore necessary that every one of the faithful should cast out demons, or raise the dead, or speak with tongues; but such a one only who is vouchsafed this gift, for some cause which may be advantage to the salvation of the unbelievers, who are often put to shame, not with the demonstration of the world, but by the power of the signs; that is, such as are worthy of salvation: for all the ungodly are not affected by wonders; and hereof God Himself is a witness, as when He says in the law: "With other tongues will I speak to this people, and with other lips, and yet will they by no means believe." [Isaiah 28:11; 1 Corinthians 14:21] For neither did the Egyptians believe in God, when Moses had done so many signs and wonders; nor did the multitude of the Jews believe in Christ, as they believed Moses, who yet had healed every sickness and every disease among them.

(Vers. 10 seqq.) Who will teach knowledge, and who will make understanding? Weaned from milk, pulled from the breasts: command, re-command; command, re-command; wait, re-wait; wait, re-wait; a little here, a little there. For with stammering lips and another tongue He will speak to this people, to whom He said, 'This is the rest, give rest to the weary,' and 'This is the refreshing,' but they would not hear. And the word of the Lord will be to them, command, re-command; command, re-command; wait, re-wait; wait, re-wait; a little here, a little there, that they may go and fall backward, and be broken, snared, and caught. LXX: To whom shall we announce evil, and to whom shall we announce good news? Those who have been weaned from milk, those who have been taken away from the breast. Expect tribulation upon tribulation; wait for hope upon hope; still little, still little: because of the mockery of lips, because of the other tongue with which they will speak to this people, saying to them: This is the rest for the hungry, and this is the crushing, and they did not want to hear. The word of the Lord will come upon them: Tribulation upon tribulation: wait, wait; hope upon hope: still little, still little; so that they may go and fall backward, and be crushed, and be endangered, and be captured. Who, he says, is worthy of the teaching of the Lord, to whom are the words of the Savior saying: 'He who has ears to hear, let him hear' (Matthew 12:15), so that what he has heard with his ears, he may understand with his heart? […]

Someone might well ask how the apostles drew to themselves all these people. How did men who spoke only the language of the Jews win over the Scythian, the Indian, the Sarmatian and the Thracian? Because they received the gift of tongues through the Holy Spirit. Not only did the apostles say this but also the prophets when they made both these facts clear, namely, that the apostles received the gift of tongues and that they failed to win over the Jews. Hear how the prophet showed this when he said, " 'In foreign tongues and with other lips I shall speak to this people, and in this way they shall not hear me,' says the Lord."

Just as sometimes all the utterances of the Old Testament together in the Holy Scriptures are signified by the name of the Law. For the apostle, in citing a text from the prophet Isaiah, where he says, "With divers tongues and with divers lips will I speak to this people," yet prefaced it by, "It is written in the Law." And the Lord Himself says, "It is written in their Law, They hated me without a cause," whereas this is read in the Psalm.

And he adds the punishment: for with the speech of lips, and with another tongue, that is, you shall so lack understanding of the prophets as if someone were speaking to you, with only the movement of the lips, and in a foreign tongue; or …