1 Corinthians 14:16-17

Otherwise if you bless [and give thanks to God] in the spirit only, how will any outsider or someone who is not gifted [in spiritual matters] say the “Amen” [of agreement] to your thanksgiving, since he does not know what you are saying? [1 Chr 16:36; Ps 106:48] You are giving thanks well enough [in a way that God is glorified], but the other person [who does not understand you] is not edified [and spiritually strengthened since he cannot join in your thanksgiving].