For if I pray ... - The reference to prayer here, and to singing in 1 Corinthians 14:15, is designed to illustrate the propriety of the general sentiment which he is defending, that public worship should be conducted in a language that would be intelligible to the people. However well meant it might be, or however the "heart" might be engaged in it, yet unless it was intelligible, and the understanding could join in it, it would be vain and profitless.

My spirit prayeth - The word spirit here (πνεῦμα pneuma) has been variously understood. Some have understood it of the Holy Spirit - the Spirit by which Paul says he was actuated. Others of the "spiritual gift," or that spiritual influence by which he was endowed. Others of the mind itself. But it is probable that the word "spirit" refers to the "will;" or to the mind, as the seat of the affections and emotions; that is, to the heart, desires, or intentions. The word "spirit" is often used in the Scriptures as the seat of the affections, and emotions, and passions of various kinds; see Matthew 5:3, "Blessed are the poor in spirit;" Luke 10:21, "Jesus rejoiced in spirit." So it is the seat of ardor or fervor Luke 1:17; Acts 18:25; Romans 12:11; of grief or indignation; Mark 3:12; John 11:33; John 13:21; Acts 17:16. It refers also to feelings, disposition, or temper of mind, in Luke 9:55; Romans 8:15. Here it refers, it seems to me. to the heart, the will, the disposition, the feelings, as contradistinguished from the understanding; and the sense is, "My feelings find utterance in prayer; my heart is engaged in devotion; my prayer will be acceptable to God, who looks upon the feelings of the heart, and I may have true enjoyment; but my understanding will be unfruitful, that is, will not profit others. What I say will not he understood by them; and of course, however much benefit I might derive from my devotions, yet they would be useless to others."

But my understanding - (ὁ δὲ νοῦς μου ho de nous mou). My intellect, my mind; my mental efforts and operations.

Is unfruitful - Produces nothing that will be of advantage to them. It is like a barren tree; a tree that bears nothing that can be of benefit to others. They cannot understand what I say, and of course, they cannot be profited by what I utter.

For if I pray in an unknown tongue - If my prayers are composed of sentences and sayings taken out of the prophets, etc., and in their own language - my spirit prayeth, my heart is engaged in the work, and my prayers answer all the purpose of prayers to myself; but my understanding is unfruitful to all others, because they do not understand my prayers, and I either do not or cannot interpret them. See the note on 1 Corinthians 14:19.

For if I pray in an unknown tongue,.... In the Hebrew tongue, which the greatest part of the Jewish doctors insisted (a) upon should be only used in prayer; which notion might be borrowed from them, and now greatly prevailed in the church at Corinth; and the custom was used by such as had the gift of speaking that language, even though the body and bulk of the people understood it not:

my spirit prayeth; I pray with my breath vocally; or else with affection and devotion, understanding what I say myself, and so am edified; or rather with the gift of the Spirit bestowed on me:

but my understanding is unfruitful; that is, what I say with understanding to myself is unprofitable to others, not being understood by them.

(a) Vid. Trigland. de Sect. Kar. c. 10. p. 172, 173.

Spirit (πνεῦμα)

The human spirit, which is moved by the divine Spirit. See on Romans 8:4.

Understanding (νοῦς)

See on Romans 7:23.

Is unfruitful (ἄκαρπός ἐστιν)

Furnishes nothing to others.

{6} For {i} if I pray in an unknown tongue, my {k} spirit prayeth, but my understanding is {l} unfruitful.

(6) A reason: because it is not sufficient for us to speak so in the congregation that we ourselves worship God in spirit

(that is according to the gift which we have received), but we must also be understood of the company, lest that is unprofitable to others which we have spoken.

(i) If I pray, when the church is assembled together, in a strange tongue.

(k) The gift and inspiration which the spirit gives me does its part, but only to myself.

(l) No fruit comes to the church by my prayers.

14:14 If I pray in an unknown tongue, etc. He does not understand, and only his spirit prayeth.

14:14 If I pray in an unknown tongue - The apostle, as he did at 1Cor 14:6, transfers it to himself. My spirit prayeth - By the power of the Spirit I understand the words myself. But my understanding is unfruitful - The knowledge I have is no benefit to others.

14. spirit-my higher being, the passive object of the Holy Spirit's operations, and the instrument of prayer in the unknown tongue, distinguished from the "understanding," the active instrument of thought and reasoning; which in this case must be "unfruitful" in edifying others, since the vehicle of expression is unintelligible to them. On the distinction of soul or mind and spirit, see Eph 4:23; Heb 4:12.

14:6-14 Even an apostle could not edify, unless he spoke so as to be understood by his hearers. To speak words that have no meaning to those who hear them, is but speaking into the air. That cannot answer the end of speaking, which has no meaning; in this case, speaker and hearers are barbarians to each other. All religious services should be so performed in Christian assemblies, that all may join in, and profit by them. Language plain and easy to be understood, is the most proper for public worship, and other religious exercises. Every true follower of Christ will rather desire to do good to others, than to get a name for learning or fine speaking.