1 Corinthians 2:4

and my speech and my preaching were not with persuasive words of wisdom, but with a demonstration of the spirit and power,

Romans 15:19

by the power of miracles and prodigies, by the power of the Spirit, so that from Jerusalem and around as far as Illyricum I have fully preached the gospel of Christ.

1 Corinthians 4:20

for the kingdom of God is not in word, but in power.

1 Corinthians 1:17

For Christ sent me not to baptize but to preach the good news, not with a wisdom of speech lest the cross of Christ should be without effect.

1 Corinthians 2:1

And when I came to you, brothers, I came not with excellency of speech, or wisdom, declaring to you the mystery of God.

1 Corinthians 2:13

which we also speak, not in words taught by human wisdom, but in those taught by the Spirit, comparing spiritual things with spiritual.

1 Thessalonians 1:5

that our gospel came not to you in word only, but with power and with the Holy Spirit and with full assurance, as you know what we were among you for your sakes.

2 Peter 1:16

For we did not follow skilfully constructed myths in making known to you the power and appearing of our Lord Jesus Christ, but were eye witnesses of his majesty.

John 16:8-15

And when he has come, he will convince the world of sin, and of righteousness, and of judgment:

Acts 20:27

for I have not kept back from declaring to you all the counsel of God.

Acts 26:28

And Agrippa said to Paul, You almost persuade me to be a Christian.

Romans 16:18

for such serve not our anointed Lord, but themselves, And by kind and complimentary words deceive the minds of the simple.

Galatians 1:10

For do I now obey man, or God? or do I seek to please men? For if I yet pleased men, I could not have been a servant of Christ.

Colossians 2:4

But I say this that no one may mislead you with persuasive words.

1 Peter 1:12

to whom it was revealed that they ministered not to themselves but to us those things which have now been declared to you by those who preached to you the good news, with the Holy Spirit sent from heaven, into which the angels desire to look.

2 Peter 2:18

For speaking extravagant words of vanity, they entice with carnal desires of lewdness those scarcely escaped from them, those living in error,

Treasury of Scripture Knowledge

Summary

And my speech and my preaching was not with enticing words of man's wisdom, but in demonstration of the Spirit and of power:

My speech

General references

Bible References

My speech

Acts 20:27
for I have not kept back from declaring to you all the counsel of God.

General references

Luke 4:32
and they were astonished at his teaching, for his word was with power.
1 Corinthians 4:20
for the kingdom of God is not in word, but in power.