1 Corinthians 14:18

I thank my God, I speak with tongues more than ye all:

Cross-reference

In 1 Corinthians 4:7, Paul warns against boasting in gifts received, tempering any pride from his claim to speak in tongues more.

Acts 2:4 Historical context

In Acts 2:4, the disciples speak in tongues at Pentecost, providing the biblical precedent for the gift Paul exercises in v18.