“I still have many things to tell you all, but you can’t handle them right now. Once that truthful Spirit comes, he’ll lead you all to all truth. He won’t speak independently. Instead, he’ll speak whatever he hears. He’ll tell you what’s coming. He’ll focus on me; he’ll take what’s mine and give it to you all. Everything the Father has is mine. This is why I said he takes what’s mine and will give it to you all.” —Jesus,
In explaining what the Holy Spirit will do for his followers, Jesus lets us in, to some degree, on how the Trinity interacts. Here he says,
What things are these? Well, first of all I expect it to be knowledge. The Father has plans for the universe, and wants us clued in on them. The Father is almighty, and wants us to participate in his activity. The Father has encouragement and information for us, and wants us to hear it and know it. The Father wants to bless us. These blessings come via Jesus—through him, in his name—to the Spirit, who gives them to us directly and efficiently.
What Jesus taught his students at this time, was actually coming to them rather inefficiently. He was trying to bless them, but his eventual arrest freaked them out, made them run away, made Simon Peter swear he didn’t know Jesus, and otherwise made them forget all the encouragement he’d given them. As powerful and influential as Jesus is, he’s limited as a human: He can’t take his things and put them inside us. He can’t embed them in our spirits, embed them in our character. He can talk, but we can ignore him. But that’s not true of the Spirit. When the Spirit doesn’t want to be ignored, it’s impossible to ignore him. When the Spirit puts something in you, it sticks.
So Jesus had to return to the Father for one simple reason: The most effective way for Jesus’s truth to be put in us, is for the truthful Spirit to put it there. Jesus can speak some of the truth, but as he said, we can’t handle all of it till the Spirit comes along to comprehensively guide us into all of it.
Jesus also points out the Spirit isn’t independent. In other words, he’s not going to do a different thing than Jesus. He’s not gonna preach a different gospel, or produce a different ministry. They work together. In fact this is how we know whether it’s really the Spirit involved in our activity, or some fraudulent spirit who’s only pretending to be God: If this spirit points to Jesus, and tries to make him central to everything we do, he’s either the Holy Spirit, or one of his angels. If this spirit doesn’t point to Jesus, but points to you, or to another person, or to a ministry or organization or philosophy or movement, or anything which doesn’t center on Jesus, it’s a fraud. If this spirit claims to point to Jesus, but teaches ridiculous things about him which are totally inconsistent with Jesus as revealed in the gospels, it’s a fraud. If it claims that the truth about Jesus can’t be found through orthodox Christianity or “organized religion,” it’s likewise a fraud. Any spirit who says Jesus isn’t human, isn’t God, or wasn’t raised from the dead, isn’t the Holy Spirit. The Spirit won’t testify to anything other than what Jesus teaches.
And since the Spirit isn’t independent, this means he’ll apply the full power of God to our lives. He isn’t on his own; he isn’t limited. He’s not weaker than Jesus, or lesser than Jesus, or inferior to Jesus. On the contrary: Jesus limited himself in order to become human, but the Spirit has no limitations whatsoever. He’s God; he’s as almighty as God is. He’s not a concession prize now that Jesus has gone to the Father: He’s the fulfillment of God’s promise to be with us forever. So let’s appreciate the Spirit for the amazing gift he is.