John 14:20

"On that day you will realize that I am in my Father, and you are in me and I am in you."

On that day
John 16:23 "In that day you will no longer ask me anything. I tell you the truth, my Father will give you whatever you ask in my name."
John 16:26 "In that day you will ask in my name. I am not saying that I will ask the Father on your behalf."

I am in my Father
John 14:10-11 "Don't you believe that I am in the Father, and that the Father is in me? The words I say to you are not just my own. Rather, it is the Father, living in me, who is doing his work. Believe me when I say that I am in the Father and the Father is in me; or at least believe on the evidence of the miracles themselves."
John 10:38 "But if I do it, even though you do not believe me, believe the miracles, that you may know and understand that the Father is in me, and I in the Father."
John 17:20-21 "My prayer is not for them alone. I pray also for those who will believe in me through their message, that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me."

and I am in you
Romans 8:10 But if Christ is in you, your body is dead because of sin, yet your spirit is alive because of righteousness.

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984 by International Bible Society. Used by permission. All rights reserved worldwide.