The second factor of a denomination is a special fellowship based upon a special teaching in a realm narrower than that of "the fellowship of the apostles" (Acts 2:42). The fellowship of the apostles is the fellowship of the entire Body universally, covering all kinds of genuine believers. Romans 14 tells us that we must receive different kinds of genuine believers, regardless of what days they observe or what dietary regulations they keep. Whether they eat herbs or eat meat, they are genuine believers because they believe in the Lord Jesus. Thus, we must receive them.
The third factor of a denomination is a special name, either according to a special teaching or according to a particular practice, that designates a certain group of believers who are of the same teaching or the same practice. The taking of such a name denominates a particular sect, making it a denomination.
Any of the above-mentioned three factors is adequate to divide the believers from others who are different from them in teaching or in practice. Therefore, although we should practice things such as baptism by immersion, the presbytery, and head covering, we should not make these things a special item that divides us from others. Furthermore, we should not make them our creed, and we should not designate ourselves by a name, such as Lutheran, Baptist, or Presbyterian, that is according to a particular teaching or practice.