Unity

I just read an interesting thought.  Patriarch Bartholomew, in the new book,  "Bartholomew- Apostle and Visionary", states lack of unity among Christians is dishonorable to God and shameful to us. .. but unity does not have to mean parity among denominations or confessional adjustment.  Nor does it entail acquiescence to doctrinal relativism or resignation to denominational minimalism.
The practice of unity between all the branches of Christianity is a very important goal.  But what would it look like?