In browsing the Forum, this thread caught my eye because some Protestants do not see any scandal in denominationalism, which is often used by Catholic apologists to “prove” the error of private interpretation of Scripture vs the Magisterium’s final authority in these matters.
Also, John 17:21 is where Jesus prays “…that they may all be one; even as You, Father, are in Me and I in You, that they also may be in Us, so that the world may believe that You sent Me.” Having many church denominations, as with Protestant and non-denominational believers, appears to go against Christ’s wish and is evidence of what happens when there is no unity under the “one, holy, Catholic Church,” and its Magisterium.
However, non-catholic christians counter this argument, saying that there IS unity among Bible believers because they all follow the essential doctrines of Christianity as found in the Scriptures, and that their spiritual unity also remains. Their differences are only in externals–e.g., church government and organization, conduct of religious services, the administration of baptism, etc.
Protestants follow Jesus’ injunction in John 13:35: “This is how all will know that you are my disciples, if you love one another.” Protestants and other Bible Christians claim more unity in essential biblical belief and practice than have Catholics who follow unbiblical Traditions which separate them from Truth.
I apologize if my comments are not directly to the point and intention of your subject matter. My hope is that although we have denominational diversity in Christianity, we all can agree on some essentials regarding the Trinity, Morality, Salvation, and the Last Things even if we don’t agree on the makeup of Scripture, validity of Tradition, Sacraments, the Virgin Mary, Purgatory, etc.