Objection 1. It would seem that the gift of tongues is more excellent than the grace of prophecy. For, seemingly, better things are proper to better persons, according to the Philosopher (Topic. iii, 1). Now the gift of tongues is proper to the New Testament, hence we sing in the sequence of Pentecost [The sequence: 'Sancti Spiritus adsit nobis gratia' ascribed to King Robert of France, the reputed author of the 'Veni Sancte Spiritus.' Cf. Migne, Patr. Lat. tom. CXLI]: "On this day Thou gavest Christ's apostles an unwonted gift, a marvel to all time": whereas prophecy is more pertinent to the Old Testament, according to Hebrews 1:1, "God Who at sundry times and in divers manners spoke in times past to the fathers by the prophets." Therefore it would seem that the gift of tongues is more excellent than the gift of prophecy.
Objection 2. Further, that whereby we are directed to God is seemingly more excellent than that whereby we are directed to men. Now, by the gift of tongues, man is directed to God, whereas by prophecy he is directed to man; for it is written (1 Corinthians 14:2-3): "He that speaketh in a tongue, speaketh not unto men, but unto God... but he that prophesieth, speaketh unto men unto edification." Therefore it would seem that the gift of tongues is more excellent than the gift of prophecy.
Objection 3. Further, the gift of tongues abides like a habit in the person who has it, and "he can use it when he will"; wherefore it is written (1 Corinthians 14:18): "I thank my God I speak with all your tongues." But it is not so with the gift of prophecy, as stated above (Question 171, Article 2). Therefore the gift of tongues would seem to be more excellent than the gift of prophecy.
Objection 4. Further, the "interpretation of speeches" would seem to be contained under prophecy, because the Scriptures are expounded by the same Spirit from Whom they originated. Now the interpretation of speeches is placed after "divers kinds of tongues" (1 Corinthians 12:10). Therefore it seems that the gift of tongues is more excellent than the gift of prophecy, particularly as regards a part of the latter.
On the contrary, The Apostle says (1 Corinthians 14:5): "Greater is he that prophesieth than he that speaketh with tongues."
I answer that, The gift of prophecy surpasses the gift of tongues, in three ways. First, because the gift of tongues regards the utterance of certain words, which signify an intelligible truth, and this again is signified by the phantasms which appear in an imaginary vision; wherefore Augustine compares (Gen. ad lit. xii, 8) the gift of tongues to an imaginary vision. On the other hand, it has been stated above (Question 173, Article 2) that the gift of prophecy consists in the mind itself being enlightened so as to know an intelligible truth. Wherefore, as the prophetic enlightenment is more excellent than the imaginary vision, as stated above (Question 174, Article 2), so also is prophecy more excellent than the gift of tongues considered in itself. Secondly, because the gift of prophecy regards the knowledge of things, which is more excellent than the knowledge of words, to which the gift of tongues pertains.
Thirdly, because the gift of prophecy is more profitable. The Apostle proves this in three ways (1 Corinthians 14); first, because prophecy is more profitable to the edification of the Church, for which purpose he that speaketh in tongues profiteth nothing, unless interpretation follow (1 Corinthians 14:4-5). Secondly, as regards the speaker himself, for if he be enabled to speak in divers tongues without understanding them, which pertains to the gift of prophecy, his own mind would not be edified (1 Corinthians 14:7-14). Thirdly, as to unbelievers for whose especial benefit the gift of tongues seems to have been given; since perchance they might think those who speak in tongues to be mad (1 Corinthians 14:23), for instance the Jews deemed the apostles drunk when the latter spoke in various tongues (Acts 2:13): whereas by prophecies the unbeliever is convinced, because the secrets of his heart are made manifest (Acts 2:25).
Reply to Objection 1. As stated above (174, 3, ad 1), it belongs to the excellence of prophecy that a man is not only enlightened by an intelligible light, but also that he should perceive an imaginary vision: and so again it belongs to the perfection of the Holy Ghost's operation, not only to fill the mind with the prophetic light, and the imagination with the imaginary vision, as happened in the Old Testament, but also to endow the tongue with external erudition, in the utterance of various signs of speech. All this is done in the New Testament, according to 1 Corinthians 14:26, "Every one of you hath a psalm, hath a doctrine, hath a tongue, hath a revelation," i.e. a prophetic revelation.
Reply to Objection 2. By the gift of prophecy man is directed to God in his mind, which is more excellent than being directed to Him in his tongue. "He that speaketh in a tongue "is said to speak "not unto men," i.e. to men's understanding or profit, but unto God's understanding and praise. On the other hand, by prophecy a man is directed both to God and to man; wherefore it is the more perfect gift.
Reply to Objection 3. Prophetic revelation extends to the knowledge of all things supernatural; wherefore from its very perfection it results that in this imperfect state of life it cannot be had perfectly by way of habit, but only imperfectly by way of passion. on the other hand, the gift of tongues is confined to a certain particular knowledge, namely of human words; wherefore it is not inconsistent with the imperfection of this life, that it should be had perfectly and by way of habit.
Reply to Objection 4. The interpretation of speeches is reducible to the gift of prophecy, inasmuch as the mind is enlightened so as to understand and explain any obscurities of speech arising either from a difficulty in the things signified, or from the words uttered being unknown, or from the figures of speech employed, according to Daniel 5:16, "I have heard of thee, that thou canst interpret obscure things, and resolve difficult things." Hence the interpretation of speeches is more excellent than the gift of tongues, as appears from the saying of the Apostle (1 Corinthians 14:5), "Greater is he that prophesieth than he that speaketh with tongues; unless perhaps he interpret." Yet the interpretation of speeches is placed after the gift of tongues, because the interpretation of speeches extends even to the interpretation of divers kinds of tongues.
Source: Summa Theologica (New Advent)