Who is Theodore of Mopsuestia?

If you know without me telling you, then I want for you to slowly put down the textbook on church history and slowly back away from the computer.  For those of you who haven't spent the past several years in a theology library cubicle Theodore of Mopsuestia was, not surprisingly, the bishop of Mopsuestia from 392 to 428 AD.  
Now that you know who Theodore is, you are probably wondering why I have brought him up.
In one of his Catechetical Homilies (also known as sermons of instruction on Christian doctrine), Theodore states that:
"It belonged to our Lord to confer the Spirit, whom he conferred now upon us in baptism as the firstfruits of the future benefits, which he will confer upon us in their entirety at the time of the resurrection."
At the heart of Theodore's statement is a very simple truth, one that often gets obscured as we go to war in our churches over what the Holy Spirit is and what it is not.  When we move from one place to another, it is a fairly common occurrence for people to exchange meaningful objects as a way of remembering each other.  Just a few days ago, I received a very artfully laid out poster and tri-board from the youth group I used to work with.  The point of both was to capture some of the most memorable moments of our time together, while also taking as many opportunities to make fun of me as possible.  I love it.  I love it because every time I look at it, I will be reminded not only of those memories, but of the fact that there is a group of teenagers in Atlanta that I care deeply about.  In a similar way, the Holy Spirit has been give by Jesus as a palpable sign of God's presence in our midst.  As we engage the world that surrounds us, it is easy to get the feeling that there is much more to be done than can be accomplished by even the most dedicated of disciples, and that feeling is justified.  I know that it's justified because in His infinite wisdom, Christ did not leave us to perform the task of reconciliation and recreation alone.  He left us the Holy Spirit, referring to it as the paraclete, and thus giving us some insight into his reasons for leaving us the Spirit in the first place.  While the name Holy Spirit goes a long way in telling us that that of which we speak is both sacred and eternal, the word paraclete is far more concerned with functionality.  It's hard to use one word to describe what paraclete means, but its generally agreed that it is some combination of helper, comforter, and advocate.  The interesting thing about this is there are words that denote action.  Help, comfort, advocate.  There is a reason why Jesus left the Holy Spirit behind to lead us in our journey of faith: He knew we needed help, and beyond that, He knew there would be times when despite their past experiences, the disciples would begin to doubt whether He ever really existed.  Years from now I will be able to take out my poster and tri-board and know that the group of teens I worked with Atlanta was more than just a figment of my imagination.  Similarly, almost 2,000 years after His resurrection the Holy Spirit testifies to us that Jesus is more than a well-written character in some fictional drama.  He was, is, and forever shall be real, because the gift that He gave us in the paraclete remains with us to this day, helping us, comforting us, serving as an advocate for us with the Father.  
In an effort to come full circle, Theodore's point is that just as baptism is the beginning of our Christian walk, so is the Holy Spirit just the beginning of God's work in our world today.  Just as our baptism symbolizes the literal resurrection that we expect to one day experience, so the Holy Spirit serves to help us envision a world where God's kingdom will be made manifest among all creation; a world where love, peace, and justice have become universal norms rather than unrealized dreams.