1 Corinthians 14:17
“For thou verily givest thanks well, but the other is not edified.”
Observe how again here he brings his stone to the plumb-line, every where seeking the edification of the Church. Now by the “unlearned” he means the laymen, and signifies that he also suffers no little loss when he is unable to say the Amen. And what he says is this: “if you shall bless in a barbarian tongue, not knowing what you say, nor able to interpret, the layman cannot respond the Amen. For not hearing the words, 'forever and ever,' which are at the end, he does not say the Amen.” Then again, comforting him concerning this, that he might not seem to hold the gift too cheap; the same kind of remark as he made above, that “he speaks mysteries,” and “speaks unto God,” and “edifies himself,” and “prays with the spirit,” intending no little comfort from these things, this also he utters here, saying, “for thou indeed givest thanks well,” since you speak being moved by the Spirit: but the other hearing nothing nor knowing what is said, stands there, receiving no great advantage by it.
7. Further, because he had run down the possessors of this gift, as though they had no such great thing; that he might not seem to hold them cheap, as being himself destitute of it, see what he says:
Source: Homilies on First Corinthians (New Advent)