NOTES for Eph 4:4-6
Paul's words about one body, one spirit, one faithfulness, and one baptism sound like one of the early Christian creeds. In those days there was no single creed; there were, apparently, several. And although no one formally canonized these creeds, in fact they played their role: they allowed Christians to formulate briefly and capaciously the main credo of their faith and life. And at the foundation of the formulation offered by the apostle in his letter lies the Church as one body and one spirit, united by one hope, the only hope for all.
The issue is precisely the Church with a capital letter. Not an earthly community founded by people, but a spiritual reality. As a spiritual reality, the Church is always the Kingdom on earth. If a Christian is by definition an inhabitant of the Kingdom, then the Church is by definition the representation of the Kingdom on earth.
Its members are united among themselves by one breath, the same for all, the breath of this Kingdom. And they are bound by one common hope: the hope that the day of Christ's return in glory will come, when the Kingdom will be revealed to the end and in fullness, including and transfiguring the whole world. Therefore all Christians have one Lord. In this case precisely Lord with a capital letter. King. Sovereign of His Kingdom. The very Kingdom into which one enters through baptism, which is also one. Of course, if there were many churches, there would also be many baptisms. But the Church with a capital letter is one by definition.
Therefore baptism is also one, if it is real: it brings a person precisely into this Church with a capital letter, not into some earthly community. Or it brings him nowhere at all, but then the word "baptism" should be put in quotation marks. And the faith of all Christians is also one, if only they are Christians. Faith, of course, as faithfulness to Christ, not as various descriptions of numerous versions of a Christian worldview. And one God over all and above all. And in all. For only God's presence can make the Church the body of Christ and the world the Kingdom. In this is the hope of Christians. If, of course, we are speaking of real Christianity.