Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works.
10. That I am in the Father, and the Father in me. I do not consider these words to refer to Christ’s Divine essence, but to the manner of the revelation; for Christ, so far as regards his hidden Divinity, is not better known to us than the Father.
You know the way better than you think. Christ is willing to make the best of your weak knowledge, seeing good in you that you cannot yet see in yourselves. Thomas shows modesty in his ignorance, and Christ's word stirs him to seek further light rather than settle for confusion.
AI summary
Commenting on John 14:4-11
Believest thou not that I am in the Father?.... This surely is, as it must needs be, and ought to be, an article of your faith, "that I am in the Father", and the Father in me; phrases which are expressive of the sameness of nature in the Father and the Son; of the Son's perfect equality with the Father, since the Son is as...