Unity requires more than equality. Unity requires humility. When Paul appeals to the church at Philippi to be unified, he does so with the example of Christ, who, being in nature God, did not consider equality with God something to grasp onto in His incarnated life. He emptied Himself, not by putting off His divine nature, but by taking on the nature of a slave, the lowest human in the Roman Empire or the Jewish world. And He kept going down, as He put Himself in the path of the cross. Jesus went as far down as a man can go as a crucified slave, and then was exalted all the way back up as glorified Lord.