1 Corinthians 14:13

14:13 So then, one who speaks in a tongue should pray that he may interpret.

1 Corinthians 14:4

14:4 The one who speaks in a tongue builds himself up, ¹  but the one who prophesies builds up the church.

[14:4]  ¹ sn The Greek term builds (himself) up does not necessarily bear positive connotations in this context.