Paul’s language in 1 Corinthians is very much that of following the pattern of teaching he has set forth. An example is the close of the first major section in chapters 1-4, in which he condemns division among their ranks and insists on the unity of the body.
I encourage you, then, be imitators of me. For this reason, I have sent Timothy to you, who is my dear and faithful son in the Lord. He will remind you of my ways in Christ, as I teach them everywhere in every church (1 Cor. 4:16-17 NET).
He uses such language repeatedly in the letter as he corrects deviations from the pattern, as well as using the language of tradition, or passing on what he has received from the Lord (cf. 1 Cor. 11:23).
If following the New Testament pattern were a matter of option, there would need be no discussion whatsoever about following this model. But here is why it matters:
Do you not know that you are God’s temple and that God’s Spirit lives in you? If someone destroys God’s temple, God will destroy him. For God’s temple is holy, which is what you are (1 Cor. 3:16-17).
The destruction of the temple of God here, within the context, refers to causing or supporting division within the church. To the people of God also applies the principle: What God has joined, let no one divide. The church is one and to divide it is to destroy it. God (this is no human speaking) will eternally destroy such people. That means that following this directive, and others like it, is a matter of salvation.
Such language of destruction and judgment occurs commonly in passages that deal with departures from the pattern. (Another example is 1 Cor. 11:27-34, where Paul repeatedly speaks of condemnation for those do not follow the pattern or tradition of eating the Lord’s Supper as the Lord gave it.)
If Paul was inspired to write such language of judgment over the differences within a single congregation, his terms apply even more to the division caused by the denominations with their separate doctrines, names, creeds, and practices. Such division is a travesty, widely recognized as such among denominationals themselves, but who nevertheless continue to perpetuate their divisions. Those who act as if it does not matter or who deny that a pattern exists destroy the church and upon them the word of God pronounces that they, too, will be destroyed for their evil work.