Access to the Father
It's fun to see how the Trinity relates to each other. They are always in cooperation, but their cooperation is always complementary. Each fulfills the same purpose, but in different ways. Paul mentioned this in Ephesians where he said Christ came and preached on this earth.
And He came and preached peace to you who were far away, and peace to those who were near; for through Him we both have our access in one Spirit to the Father (Eph 2:17-18).
Jesus came as a full representative of God the Father and he established the basis of peace with the Trinity. And he established a very practical access for us to God the Father. He opened the way to a fellowship with heaven but he also gave us the empowerment to take advantage of that access. When he left, he sent the person of the Holy Spirit to take over where he left off. So that we would have the help our hearts so desperately need. So he opened the door, the Holy Spirit carries us through the door, and God the Father is on the other side of the door waiting for us. Each of them has a different role but all of them have the same goal, to draw us into a heavenly relationship.