Objection 1: It would seem that a gratuitous grace does not attach to words. For grace is given for that which surpasses the faculty of nature. But natural reason has devised the art of rhetoric whereby a man is able to speak so as to teach, please, and persuade, as Augustine says (De Doctr. Christ. iv, 12). Now this belongs to the grace of words. Therefore it would seem that the grace of words is not a gratuitous grace.
Obj. 2: Further, all grace pertains to the kingdom of God. But the Apostle says (1 Cor. 4:20): "The kingdom of God is not in speech, but in power." Therefore there is no gratuitous grace connected with words.
Obj. 3: Further, no grace is given through merit, since "if by grace, it is not now of works" (Rom. 11:6). But the word is sometimes given to a man on his merits. For Gregory says (Moral. xi, 15) in explanation of Ps. 118:43, "Take not Thou the word of truth utterly out of my mouth" that "the word of truth is that which Almighty God gives to them that do it, and takes away from them that do it not." Therefore it would seem that the gift of the word is not a gratuitous grace.
Obj. 4: Further, it behooves man to declare in words things pertaining to the virtue of faith, no less than those pertaining to the gift of wisdom or of knowledge. Therefore if the word of wisdom and the word of knowledge are reckoned gratuitous graces, the word of faith should likewise be placed among the gratuitous graces.
On the contrary, It is written (Ecclus. 6:5): "A gracious tongue in a good man shall abound [Vulg.: 'aboundeth']." Now man's goodness is by grace. Therefore graciousness in words is also by grace.
I answer that, The gratuitous graces are given for the profit of others, as stated above (I-II, Q. 111, AA. 1, 4). Now the knowledge a man receives from God cannot be turned to another's profit, except by means of speech. And since the Holy Ghost does not fail in anything that pertains to the profit of the Church, He provides also the members of the Church with speech; to the effect that a man not only speaks so as to be understood by different people, which pertains to the gift of tongues, but also speaks with effect, and this pertains to the grace of the word.
This happens in three ways. First, in order to instruct the intellect, and this is the case when a man speaks so as to teach. Secondly, in order to move the affections, so that a man willingly hearkens to the word of God. This is the case when a man speaks so as to please his hearers, not indeed with a view to his own favor, but in order to draw them to listen to God's word. Thirdly, in order that men may love that which is signified by the word, and desire to fulfill it, and this is the case when a man so speaks as to sway his hearers. In order to effect this the Holy Ghost makes use of the human tongue as of an instrument; but He it is Who perfects the work within. Hence Gregory says in a homily for Pentecost (Hom. xxx in Ev.): "Unless the Holy Ghost fill the hearts of the hearers, in vain does the voice of the teacher resound in the ears of the body."
Reply Obj. 1: Even as by a miracle God sometimes works in a more excellent way those things which nature also can work, so too the Holy Ghost effects more excellently by the grace of words that which art can effect in a less efficient manner.
Reply Obj. 2: The Apostle is speaking there of the word that relies on human eloquence without the power of the Holy Ghost. Wherefore he says just before (1 Cor. 4:19): "I . . . will know, not the speech of them that are puffed up, but the power": and of himself he had already said (1 Cor. 2:4): "My speech and my preaching was not in the persuasive words of human wisdom, but in the showing of the spirit and power."
Reply Obj. 3: As stated above, the grace of the word is given to a man for the profit of others. Hence it is withdrawn sometimes through the fault of the hearer, and sometimes through the fault of the speaker. The good works of either of them do not merit this grace directly, but only remove the obstacles thereto. For sanctifying grace also is withdrawn on account of a person's fault, and yet he does not merit it by his good works, which, however, remove the obstacles to grace.
Reply Obj. 4: As stated above, the grace of the word is directed to the profit of others. Now if a man communicates his faith to others this is by the word of knowledge or of wisdom. Hence Augustine says (De Trin. xiv, 1) that "to know how faith may profit the godly and be defended against the ungodly, is apparently what the Apostle means by knowledge." Hence it was not necessary for him to mention the word of faith, but it was sufficient for him to mention the word of knowledge and of wisdom.