Question: Christians that believe in the Trinity believe that God the Father, God the Son, and God the Holy Ghost are one and the same God. How then, do they explain [John 17:21](http://www.biblegateway.com/passage/?search=John%2017:21&version=NIV) where Jesus prays that his disciples "may be one; as thou, Father, art in me, and I in thee, that they also may be one in us"?

Are the disciples supposed to become one with each other in the same way that God the Son is with God the Father?

Two other similar phrases appear in the same chapter:

v. 11: "that they may be one, as we are"

v. 22-23: "And the glory which thou gavest me I have given them; that they may be one, even as we are one: I in them, and thou in me, that they may be made perfect in one"

Answer: 
Read it in the context as one in purpose, yet separate in person... [John 1:1-14](http://biblia.com/bible/nasb95/John%201.1-14)

While I am a separate person, in purpose I am in unity and the same as other followers of Christ.

To quote a [sermon of John MacArthur's](http://www.gty.org/resources/sermons/1569/jesus-prays-for-us-part-2):

> 
> He [Jesus] prays that there may be a spiritual, holy, loving oneness, a visible oneness that the world can see in order that they may believe.
> 
> 
>
Jesus is both Divine and human. So one simple answer is to take it that the disciples, as human beings, would have the same close relationship with God as Jesus in His human nature does.

This was fulfilled at Pentecost, with the indwelling of the Holy Spirit. And its for all believers.