When we read through the New Testament we repeatedly come across the phrases "in Jesus," "in Christ," and "in Him." Everything we have in this life is a gift of God through Jesus Christ. He is in every way our cornerstone.
Specifically, Christ is the source of our unity as his followers. He made salvation occur, he chose each one of us, and he unites us. Our togetherness is based in him. We are united in a person.
Too often within the church we act as if our unity is based upon a set of beliefs. We see one group of believers holding to this set, while another holds to that set. The implication is that we can only truly be united because of what we have deemed to be important.
Jesus never said that our unity was based on a list of any kind. Rather, it's based in him. Of course, we must believe in the Jesus of the bible to be one in him. However, the unity is strictly in him and not in our own lists.
As I read John 17 what strikes me is the absolute lack of loopholes for unity in the church. Christ expects his body to be one. He gives no way out. The language of John 17 strongly implies that this is not some sort of theoretical unity. Rather, Jesus is talking about real unity in the trenches of life.
In light of our unity in him, nothing should separate us from brothers and sisters in Christ. This does not mean that we will hold to all the same beliefs. However, our differences should not divide us.
Fighting for unity is something that takes effort. Let's face it: it is easy to hang with the people we agree with. For me, it's simpler to spend time with believers who hold to simple church principles. I admit it.
God is not pleased if I only spend time with believers who hold to simple church principles. The Creator demands that I be one with all his followers. He demands the same of you.
There is no way we can be one if we view our unity as based in a statement of beliefs. We will always have some differences with most other believers. Lists might bring clarity of thought (and thus aren't all bad), but they also tend to divide.
If we rightly see that our unity is based in Christ, then it can be a reality. He is the source and the enabler of unity. We are one in him. As we talk with other believers, when our focus is Jesus it tends to unite us. Let's spend a lot of time talking about him.