"Do nothing out of rivalry or conceit, but in humility consider others as more important than yourselves. Everyone should look out not only for his own interests, but also for the interests of others. Make your own attitude that of Christ Jesus." Philippians 2:3-5
We don't have to manufacture the unity and humility that Scripture is speaking of. We don't have to try and make it happen. It is already ours in Christ Jesus. Spiritual disunity in the Church is a result of pride, arrogance and looking to our own interests. But this, clearly, is our issue, not God's.
By design, all who are truly in Christ have unity with one another. And so long as we abide in Christ, our unity is apparent. The problem is that most Christians abide in church doctrines, traditions, and theological systems instead of abiding in Christ Himself. It's not that doctrines and traditions and systematic theology are wrong things -it's just that if we love our doctrines and traditions more than we actually love Jesus, the resulting disunity will also be apparent.
That what separates us as Believers seems more obvious than what unites us ought to be a glaring wake-up call. Respect theology and traditions -but love Jesus and love each other.