John 17:20-21 (KJV) Neither pray I for these alone, but for them also which shall believe on me through their word; 21 That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
Many in the ecumenical movement use verse 21 to try to get all denominations to join together. After all, the Lord Jesus Christ is praying for us to be one, right? But notice verse 20. He says he is praying for all who will believe – not just those who are alive at the moment. He wants all believers to know and believe the same doctrines – the ones taught in God’s word. If your doctrines do not agree with the scriptures, I cannot be united with you.