1 Corinthians 14:17

For thou verily givest thanks well, but the other is not edified.

'verily givest thanks well' -'you are giving thanks well enough' (NASV) The prayer is excellent. Paul isn't running down the gift of tongues or even using your gift in prayer. Rather he is correcting an abuse. Exercising your gift when praying, when nobody in the congregation understands the language that you are praying in.

Point to Note:

In these passages we have learned that the gift of tongues under consideration could be used to express. prayer to God and to sing. psalm. Clearly, the tongues aren't gibberish.

'but the other is not edified' -and that is the problem. 'Such worship is sincere, but it is unprofitable to the hearers.' (Erdman p. 145)