Or do you not know that he who is joined to a harlot is one body with her? For it is said, “The two shall become one flesh.” But he who is joined to the LORD is one spirit with Him. 1 Corinthians 6:16–17

I do not pray for these alone, but also for those who will believe in Me through their word; that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me. And the glory which You gave Me I have given them, that they may be one just as We are one. John 17:20–22