What I see that constitutes unity in the Biblical scriptures is Oneness in Christ, which Christ is also One with the Father. One body, same mind and one Spirit in Christ. Do Muslims follow and confess the Christ Jesus of the Bible? I don’t think so. How then are we to be one with them? The Jewish religious ruler-ship in the time of Christ had a similar problem. They worshiped the God of Abraham in speech and doctrine but their hearts were far from God. The early church became separated from Judaism , first as being thought of socially as a sect of Judaism, and then as doctrine and beliefs emerged more formally from the early church, they were thought of as a different religion by faithful Jews. Jesus Christ was the stumbling block to the unity of these two groups. This remains the same today. There can be no unity in Spirit if one group is in Christ and the other group is not.
Not only is belief in Jesus Christ as the Son of God an issue, but the heart of each man must be in Christ. We must love God, trust God, and look to God in our daily lives. Our lives are directed by the Bible, the Holy Scriptures. We must put off the old man and put on Christ.
It appears that faithful Jews and faithful Muslims cannot meet this criteria. What about other religions? The only question in my mind are those religions who confess the work of Christ on the cross and elsewhere, which would be the Catholics. This religion however has muddied the waters by introducing contrary practices than those set out in the Bible. Some of these being the exaltation and prayers to Mary and the saints in the Catholic church. Scripture admonishes us to worship God exclusively. This is what He requires from us in the Ten Commandments and again in the New Testament. ‘Love God and love your neighbor as yourself’.
To love our neighbor does not mean that we should accept and entangle ourselves with different religious beliefs and doctrines to show God’s love. What then is Pope Francis attempting to do? To make friends? To get a consensus of what constitutes and makes up the church according to our world? Is his purpose to gather a larger group of people which together might have more power and say in the affairs of this world? This kind of unity would not be Scriptural or Spiritual in my mind