Baptism and Supper
Jesus established, clearly, two materialistic sacraments, that leads us to the spiritual: baptism and the supper. 1st John 5:
8- And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one
These are the fundamental basis of Christianism. Men of the Churches around the world, with their wrong purposeful interpretations of the Bible, made many forms of baptism and suppers, made a hell of confusion, like Jesus said to Nicodemus - John 3: 12- If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you [of] heavenly things?
Christian religion divided in many denominations, with the purpose of division and confusion, they invented several materialistic rituals, different than the ones established by Christ, caring more about the material and ignoring the spiritual.

Even if all immersionists where right, they couldn´t condemn, more if they are wrong, saying that whoever doesn´t go down the waters, doesn´t have salvation. With this, take members from other Churches, by the way of baptism, which has a little importance, but was a motive for a lot of confusion and division in Church.
The problem is going to be what Jesus said: The way you judge, you´ll be judged.
The way you condemn, you´ll be condemned.
And Jesus established the baptism and supper for union, never to disunite.
They never question with the purpose of building the church, but to divide. And to bring more supporters, place the importance of salvation in the form of baptism, materialize the spiritual, burying in the water, to rise from the water (neither Jesus nor Paul referred to this kind of baptism, you only have to read the texts of John 3 and Romans 6).