1 Corinthians 14:14

For if I pray in a tongue, my spirit prays, but my mind is unfruitful.

1 Corinthians 14:2

For one who speaks in a tongue does not speak to men but to God; for no one understands, but in his spirit he speaks mysteries.

1 Corinthians 14:15-16

What is the outcome then? I will pray with the spirit and I will pray with the mind also; I will sing with the spirit and I will sing with the mind also.

1 Corinthians 14:19

however, in the church I desire to speak five words with my mind so that I may instruct others also, rather than ten thousand words in a tongue.

Treasury of Scripture Knowledge

Summary

For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.

Bible References

My spirit

1 Corinthians 14:2
For one who speaks in a tongue does not speak to men but to God; for no one understands, but in his spirit he speaks mysteries.