In Ephesians 4:4-6 we read of seven ones. “There is one body, and one Spirit, just as you were called in one hope of your calling; one Lord, one faith, one baptism; one God and Father of all, who is above all and through all, and in you all.” Notice there is only one of each.
There is only one body. Ephesians 1:21-22 says that Christ is the “head over all things to the church, which is His body.” So the one body is the one blood bought church of Christ (Acts 20:28, Romans 16:16). This is the only church that Christ is going to save (Ephesians 5:23).
There is only one Holy Spirit. The Holy Spirit was given to the apostles and other inspired writers of the New Testament to guide them into all truth (John 16:13). Since the New Testament has been once and for all delivered to us (Jude 3), we no longer need further revelations as some falsely claim.
The one hope of our calling is for the salvation in Heaven (1 Peter 1:3-4) and Jesus is the author of salvation unto all that obey Him (Hebrews 5:9). This one hope is not to live here on a renewed earth for eternity as some falsely teach. This earth is going to be burned up (2 Peter 3:10).
There is only one Lord Jesus Christ, not Mohammed or anyone else. In John 14:6 Jesus says, “I am the way, the truth, and the life. No one comes to the Father except through Me.” Jesus asks, “why do you call Me ‘Lord, Lord’, and not do the things which I say?” (Luke 6:46).
There is only one faith, not the hundreds of different faiths that have been established by men today. This one faith has once and for all been delivered to us in the New Testament (Jude 3). All of the other faiths by men are vain.
There is only one baptism which is a burial in water (Romans 6:4) of those who are capable of believing and repenting. It is for the forgiveness of sins so we can be saved (Acts 2:38, Mark 16:16). All other baptisms that man has come up with are vain.
And there is only one God. There are many other false gods and millions of Hindu gods, but there is only one true God. All these other gods that man has made are false.