He said among all the faiths in the world, ONLY ONE was the correct one. IT WAS ONCE delivered, which means there was no later delivery of a different faith, since the ONE faith delivered to the saints was the only faith to be ever believed. So therefore we should never even consider another option. There is only one baptism, and it is Baptism into Jesus Christ. Baptism is included in this list of perfect unity.
Baptism is absolutely necessary.
So we have perfect unity. This final point is very important. It ends it all. Not two, or three. THE GOAL of the believer who gets into the Body.