Psalm 133 tells us that it is good and pleasant when brothers dwell in unity.
To David, unity was like the precious oil on the beard of Aaron, running down on the collar of his robes. It was like the dew that falls on the mountains of Zion, which the Lord had commanded his blessing of life forevermore.
Just like Paul said to the Philipians in Philippians 2:2, it completed his joy when the brothers were of the same mind, having the same love, and being in full accord with one mind. Paul preached many sermons and wrote many letters on harmony, unity, and love. They were all part of each other. Paul said in Colossians 3:14 that Love was the key, it is Love that binds everything together in perfect harmony.
This teaching of Love should not end with the Apostle Paul. Jesus Christ did not die on the cross for all mankind to separate themselves into smaller groups that fellowship only among themselves, Christ gave a Great Commission for all Christians to go forth and spread His Love to the rest of the world.
As Christians, we should ask ourselves: Are we in unity? Do we have this Divine Love, or do we have something else? Does our small church separate itself from other Christians of the world, refusing fellowship with our brothers? Do our churches even separate themselves from similar churches of like faith? Can like faith even be found in our religious structure and organization? Have we strayed from the Unity that was taught from the pages of the Old Testament to the New, trading Divine Love for our own traditions?