John Calvin Commentary John 10:38

"But if I do them, though ye believe not me, believe the works: that ye may know and understand that the Father is in me, and I in the Father." — John 10:38 (ASV)

But if I do. He shows that they are plainly convicted of unbelieving and sacrilegious contempt, because they give no reverence or honor to what are undoubtedly the works of God. This is a second concession, when he says, “Though I allow you to doubt my doctrine, you cannot deny, at least, that the miracles which I have performed are from God. You therefore openly reject God, and not a man.”

That you may know and believe. Though he places knowledge before faith, as if faith were inferior to it, he does so because he is dealing with unbelieving and obstinate men, who never yield to God until they are vanquished and constrained by experience; for rebels wish to know before they believe. And yet our gracious God shows us such favor that he prepares us for faith by a knowledge of his works. But the knowledge of God and of his secret wisdom comes after faith, because the obedience of faith opens to us the door of the kingdom of heaven.

That the Father is in me, and I in him. He repeats the same thing which he had said before in other words, I and my Father are one. All points to this: that in his ministry there is nothing contrary to his Father. “The Father,” he says, “is in me; that is, Divine power is manifested in me.”

And I am in my Father; that is, “I do nothing but by the command of God, so that there is a mutual connection between me and my Father.” For this discourse does not relate to the unity of essence, but to the manifestation of Divine power in the person of Christ, from which it was evident that he was sent by God.