Trinitarians claim this verse indicates 'Jesus is God' because Jesus is declaring to have oneness with God. Many Trinitarians are conditioned to read this verse as if it said, "I and the Father are one [God]" or "I an nd the Father are one [essence/nature]" as if Jesus was referring to fourth century Athanasian philosophy.
The Claim vs. The Facts
The Scriptural facts show us that Jesus is saying that he and the Father are one in terms of purpose and will and the works he was doing in the name of the Father.
The Problem with the Claim
1. Eisegesis Again
Trinitarians condition themselves and others to imagine their preconceived notions into the text and this is just one more of numerous places where they just go ahead and do it by an act of their own will. Here they imagine Jesus to be saying "I am the Father are one {God}" or "I and the Father are one {divine substance}" or some similar idea. However, there is no need to suppose Jesus had anything of the sort in mind especially in view of the context.
The Trinitarian apologist loves to cite this passage because his doctrine says there are three persons "in one." However, the obvious question in this passage is, "one what?" How are they one? Just how is Jesus one with the Father? This is not a question the Trinitarian wishes to bother entertaining. He would rather imagine for himself that Jesus and the Father are "one God" or that Jesus and the Father are "one nature" or that Jesus and God are "one substance."
2. You and Me and the Father and Jesus are one
At John 17:20-23, Jesus prays for his disciples,
"that they may all be onejust as as You Father are in me and I in You.... that, they may be one, just as we also are one, I in them and You in me, that they may be perfected in one."
Jesus prays that Christians will be one with the Father and he himself JUST AS he is one with the Father. It does not mean they are therefore "God." Here we can see clearly that Jesus sees this oneness in terms significantly different than what the Trinitarian would have us believe. For this reason, Trinitarians usually disingenuously disregard John 17 when citing John 10:30 for the sake of their doctrine.
Analysis of the Facts
1. Jesus explains how he was one with the Father - United Will
Jesus tells us that he did not come to do his own will but only the will of the Father (6:38). He also tells us he only said what the Father told him to say (8:26,28; 12:49-50; 14:24) and he was not able to do anything from himself but only what he saw the Father doing (5:19ff.). He kept his Father's word (8:55). Throughout the Gospel of John, Jesus reminds us over and over in similar ways. He was one with the Father in terms of purpose and will because he always obeyed the Father and kept His word. Jesus did not do his own will. There was only one will between the Father and Son, the Father's will.
My food is to do the will of him who sent me, and to accomplish His work.
(Jn 4:34; cf. 17:1-5).
2. Unity of Purpose and Will: The Works of the Father
Jesus tells us plainly in the Scriptures he was one with the Father in terms of the works he was doing - the works of the Father. He was one with his Father in what he did in his actions, in function and purpose, not in what he was by nature. In fact, Jesus has told his disciples, "Truly, truly, I say to you, he who believes in me will also do the works that I do and greater works than these will he do, because I go to the Father." (14:12). The unity which Jesus discusses throughout John is a oneness of function, a unity of purpose and will, the same oneness of purpose and will as he was praying for his disciples in John 17. He denied his own will to do the will of the Father and carry out His purpose and will and finish His work.
My Father is working until now, and I myself am working. 5:17
For the Father loves the Son, and shows him all things that he himself is doing, and the Father will show him greater works than these. 5:20.
...the works which the Father has given me to finish, the very works that I do, testify about me, that the Father has sent me. 5:36 (see 17:4).
the works that I do in the name of my Father, these testify of me. 10:25 (see 5:43).
I showed you many good works from the Father. 10:32.
If I do not do the works of my Father, do not believe me; but if I do them, though you do not believe me, believe the works, so that you may know and understand that the Father is in me, and I in the Father. 10:37-38 (see 17:20-23).
Do you not believe that I am in the Father and the Father in me? The words that I say to you I do not speak on from myself, but the Father abiding in me does the works. Believe me that I am in the Father and the Father in me or else believe me because of the works themselves...Truly, truly, I say to you, he who believes in me will also do the works that I do and greater works than these will he do because I go to the Father." 14:10-11; see 17:20-23).
In fact, we find the very same thing at John 5:36 which is the verse directly preceding the passage where Jesus tells the Jews they have never seen God the Father.
But He answered them, "My Father until now works, and I work... Truly, truly, I say to you, the Son can do nothing from himself, but only what he sees the Father doing. For whatever He does the Son likewise does. For the Father loves the Son, and shows him all things that He Himself is doing and the Father will show him greater works than these, so that you will marvel... But I have the greater testimony than John. For the works which the Father gave me, that I should finish them, the works themselves that I do testify concerning me that the Father has sent me. (5:17-36; cf. 4:34).
And Jesus tells the Jews this very same thing again and again but they do not listen. Indeed, he tells us that the way he is one with the Father is in what he does right here in this very passage.
If You are the Christ, tell us plainly." Jesus answered them, "I told you, and you do not believe. the works that I do in the name of my Father, these testify of me... I and the Father are one. The Jews picked up stones again to stone him. Jesus answered them, "I showed you many good works from the Father..... If I do not do the works of my Father, then do not believe me, but I do them, though you do not believe me, believe the works, so that you may know and understand that the Father is in me, and I in the Father." (John 10:25-38; see John 15:21-25; 17:20-23).
Plainly, Jesus tells us in this passage that he is one with the Father in terms of the works that he does from his Father who sent him. Jesus was one with his Father in purpose and will.
3. Context
The immediate context concerns the Father and Son's united purpose and will concerning the sheep.
My sheep hear my voice, and I know them, and they follow me and I give eternal life to them, and they will never perish; and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all and no one is able to snatch them out of the Father’s hand. I and the Father are one.”
Conclusion
How was Jesus one with the Father? If we are honest with ourselves, we can see that he was one with the Father the same way his disciples are expected to be with God, in the unity of the Holy Spirit in terms of purpose and will. This is precisely the manner in which he was praying in Gethsemane for all believers to be one with him and the Father, they in us, and us in them. Clearly, the oneness of Jesus and the Father in these passages refers to oneness of function in the unity of the Holy Spirit of God. He was one with the Father in purpose and will and for this reason he prays for his disciples to be one with him and the Father, just as we are one.
The Father who abides in me does the works. (John 14:10).
