John Whitcomb Jr. "Diversity and division is infinitely more precious than a satanic unity. The problem God's people are facing today: Satan wants unity in what? -- in error. God would infinitely prefer division because of truth. Do you know what Jesus said in Matthew 10? He said, 'I have come not to bring peace, not to bring unity, but to bring division, to set a son against his father, a daughter against her mother, so that people within their own households will be enemies of each other.' That is what Jesus said he came to do ... God's smashing of satanic ecumenical unity was an incredible blessing [Genesis 11: the Tower of Babel] ... The potential for satanic depravity is infinite, as long as what continues? -- a unity in error -- organized blasphemy. Measure this friends. Grasp it. Satan will, in his brief hour, at the end of this world, be given his opportunity to demonstrate what total unity is like in the human race, when every person will have a mark on the forehead or right hand, and will walk lockstep under incredible blasphemy ...
"You say, 'We want unity.' Oh, really? What kind of unity? 'We want all the churches to get together.' Oh, really? You mean in error, in confusion, in heresy? That is, dear friends, the ecumenical movement of our hour, in which all the great denominations and all the great church leaders are becoming more and more unified. In what? -- in compromise and theological error; and this is the ultimate horror" (from Human Races, a message delivered at Indian Hills Community Church, Lincoln, Nebraska, Fall of 1984).
Hopefully we are all members of the local church, and when you come together, you have practical unity.
together you present the Christian faith to the community.
You take the Lord's Supper together, you pray for each other, you pool your offerings together, and accomplish things together that none of you could do by yourselves.
You might say the apostles Creed together, and sing the same words of the same hymn in unity.
The main way we can have practical unity right now, is to become a member of the local church.
You can a member of a local church, or ten other churches, church obviously does not bring unity, unity will be where there is agreement with the word and the holy spirit is free to do as he wills.