Galatians 1:20

Now [realizing I am] in God's presence, I am not lying about any of these things.

Romans 9:1

I am telling [you] the truth in Christ [i.e., since I am a Christian]; I am not lying. My conscience, [confirmed] by the Holy Spirit, supports my statements [as true],

2 Corinthians 11:31

The God and Father of the Lord Jesus, who should be praised forever, knows that I am not lying.

2 Corinthians 11:10-11

As sure as the truth of Christ is in my heart, no one will stop me from boasting about this [arrangement] throughout the regions of Achaia. [Note: This was the province where Corinth was located].

Treasury of Scripture Knowledge

Summary

Now the things which I write unto you, behold, before God, I lie not.

Bible References

Behold

Romans 9:1
I am telling [you] the truth in Christ [i.e., since I am a Christian]; I am not lying. My conscience, [confirmed] by the Holy Spirit, supports my statements [as true],
2 Corinthians 11:10
As sure as the truth of Christ is in my heart, no one will stop me from boasting about this [arrangement] throughout the regions of Achaia. [Note: This was the province where Corinth was located].