NOTES for Joh 14:1-11
In mathematics, the equality of two sets can be proved this way: first it is shown that all the elements of the first set belong to the second, and then the reverse - all the elements of the second belong to the first. And it turns out that this mechanism applies far beyond mathematics. As we read today in the Gospel, Jesus Himself uses it, saying: "I am in the Father and the Father is in Me" (John 14:10).
We do not know why He does not tell the disciples directly that He and the Father are one, since He had already said this publicly (see John 10:30). Perhaps to the people closest to Him He wants not simply to report this as a fact, but also to explain why it is so. This is enough for our understanding of how the Father and the Son can be one: everything one does is done through the other and in the other. If we try to penetrate fully and lay out "on shelves" the mechanism of the inner unity of our God, nothing may come of it. The Lord asks us simply to believe that it is so. And if we cannot, then simply to look at what Christ does and in this recognize the Father (see John 14:11).