The disciples found it difficult to get their arms around Jesus’ concept of union, notes Puritan Thomas Goodwin in his Works (9:114). He makes this point from John 14:1­–26. The passage is an interesting one.

• In 14:1–9 Jesus says that to believe in himself is to believe in God. Jesus is “the way” to God.
• In 14:10–14 Jesus takes it to another level by saying he dwells “in the Father” and that the Father dwells “in me.”
• In 14:15–19 Jesus then tells them to anticipate the arrival of the Holy Spirit.
• In 14:20 Jesus presses even further: “In that day you will know that I am in my Father, and you in me, and I in you.”

Jesus continues stacking the line of thought until he delivers verse 20. If the disciples were perplexed at the first idea (and they were; see v. 9), how much more perplexed as the line of reasoning continued to develop? The whole trajectory of thought must have been overwhelming. In effect Jesus introduces what will get filled out in John’s writings as something of a triangle* of abiding: believers abide in the Savior (and vice versa), the Savior abides in the Father (and vice versa), and the Father abides in believers (and vice versa; see 1 John 4:12–16).

Goodwin wants us to note the immanence of the Holy Spirit. He was coming to help the disciples make some sense of it all (vv. 25­–26).

* Oepke, TDNT, 2:543