Jesus says this in John 14:20: “On that day you will know that I am in My Father, and you are in Me, and I am in you.” He also prays it in John 17:21. Click here for additional info.
Where in the Bible Does Jesus Say “I am in you and you are in me”?
The clearest statement is John 14:20: “On that day you will know that I am in My Father, and you are in Me, and I am in you.” Earlier in the same conversation Jesus says, “I am the way and the truth and the life. No one comes to the Father except through Me” (John 14:6), and, “If anyone loves Me, he will keep My word. My Father will love him, and We will come to him and make Our home with him” (John 14:23).
John 17:21
In His prayer before His arrest, Jesus prays the same truth: “that all of them may be one, as You, Father, are in Me, and I am in You. May they also be in Us, so that the world may believe that You sent Me” (John 17:21).
Galatians 2:20
Paul describes the same reality from the believer’s side: “I have been crucified with Christ, and I no longer live, but Christ lives in me. The life I live in the body, I live by faith in the Son of God, who loved me and gave Himself up for me” (Galatians 2:20).
John 15:4
Jesus also pictures this mutual indwelling as a vine and its branches: “Remain in Me, and I will remain in you. Just as no branch can bear fruit by itself unless it remains in the vine, neither can you bear fruit unless you remain in Me” (John 15:4).
What Does This Mean for Christians?
For Christians, these verses describe a real, ongoing union between Jesus and believers: Christ living in them by the Spirit, and they living in Him.
Summary
Jesus says “I am in you and you are in me” most directly in John 14:20, and prays it again in John 17:21. Paul and Jesus Himself describe the same union in Galatians 2:20 and John 15:4.