2 Corinthians 11:6
But though [I be] rude in speech, yet not in knowledge; but we have been throughly made manifest among you in all things.
Note 11 at 2Co 11:6: Any inadequacy that Paul may have had in his speech (see note 16 at 2Co 10:10) was more than compensated for by his knowledge. Paul's revelation knowledge (see note 1 at Lu 2:26, note 4 at 1Co 2:9, note 5 at 1Co 2:10, note 6 at 1Co 2:11, note 7 at 1Co 2:12, and note 8 at 1Co 2:13) of God and His Gospel was so powerful, it changed lives. Paul also used miraculous demonstrations of the Holy Spirit to persuade the people (see note 4 at 1Co 2:4) so that the Corinthians had gotten the full manifestation of what God had put in Paul. There are more ways to communicate the Gospel than just in word only (see note 4 at Ac 4:30).