It seems that there is some form of hierarchy within the Trinity.
For example, these passages seem to indicate that the Holy Spirit is subservient to the Father and Jesus:
John 14:26 (NIV)
But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you.
John 15:26 (NIV)
When the Advocate comes, whom I will send to you from the Father—the Spirit of truth who goes out from the Father—he will testify about me.
Also, it seems that the Father has control over Jesus:
Matthew 26:39 (NIV)
Going a little farther, he fell with his face to the ground and prayed, “My Father, if it is possible, may this cup be taken from me. Yet not as I will, but as you will.”
My understanding is that the Trinity is three persons in one God. Therefore, each person in the Trinity is equal to the other two. Yet, the verses above seem to indicate that there's a hierarchy.
Is there a hierarchy (and my previous understanding flawed) or is there a deeper understanding of what's going on in those verses above?
I'm seeking a Mainstream Protestant exegesis and viewpoint on this issue.