Apostolic Constitutions : 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. — Apostolic Constitutions (Book VIII), Section 1, I Augustine of Hippo : 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. — ON THE TRINITY 15:17.30 Gregory of Nazianzus : They spoke with strange tongues and not those of their native land; and the wonder was great, a language spoken by those who had not learned it. And the sign is to them that do not believe, not to them that believe, that it may be an accusation of the unbelievers, as it is written, "With other tongues and other lips will I speak to this people, and not even so will they listen to me, says the Lord." But they heard. Here stop a little and raise a question. How are you to divide the words? For the expression has an ambiguity, which is to be determined by the punctuation. Did they each hear in their own dialect so that if I may so say, one sound was uttered but many were heard; the air being thus beaten and, so to speak, sounds being produced more clear than the original sound? Or are we to put the stop after "they heard" and then to add "them speaking in their own languages" to what follows, so that it would be speaking in the hearers' own languages, which would be foreign to the speakers? I prefer to put it this latter way; for on the other plan the miracle would be rather of the hearers than of the speakers; whereas in this it would be on the speakers' side. And it was they who were reproached for drunkenness, evidently because they by the Spirit wrought a miracle in the matter of the tongues. — ON PENTECOST, ORATION 41:15 John Chrysostom : 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." — DEMONSTRATION AGAINST THE PAGANS 7:2