'It is I' in the Bible

To the rest it is I who am speaking, not the Lord. If any brother has a wife who is not a believer, if he is willing to live with her, let him not send her away.

But if the unbelieving partner be determined to leave, separation let it be. In such cases the believing husband or wife is not under bondage. But it is into peace that God has called us.

It is in your own interest that I say this; not that I may entangle you in a snare, but that I may help you to serve the Lord with fitting and undistracted service.

But whether it is I or they, thus do I preach, and thus you came to believe.

So it is in the resurrection of the dead. It is sown in corruption, It is raised in incorruption;