30 I and my Father are one.
31 Then the Jews took up stones again to stone him.
This passage is oft quoted by trinitarians as clear evidence that Jesus claimed to be God - he was claiming to be ontologically one with the Father.
The principle difficulty of John 10:30 for the trinitarian is that to read it in the trinitarian sense requires 'confusing the persons' - which the trinitarian model does not permit.
Here, Christ is not calling himself 'God' - if the trinitarian is to be believed, he is calling himself 'the Father'. You should know that it is heresy to say that the son and the Father are one person, but this is apparently what Christ is doing here. Certainly he is not claiming to be God - the problem for the trinitarian is far greater than that!
So what is Christ saying? He is speaking of a particular unity which he has with the Father - but what unity? Fortunately, he tells us.
The very unity of which Christ speaks here is the unity he wishes the disciples to have with himself and the Father.