In The Great Heresies Hilaire Belloc wrote this about heresy in general.
“The word [heresy] is derived from the Greek verb Haireo, which first mean “I grasp” or “I seize,” and then came to mean “I take away.” (pg. 2)
“The denial of a scheme wholesale is not heresy, and has not the creative power of heresy. It is of the essence of heresy that it leaves standing a great part of the structure it attacks. On this account it can appeal to believers andn continues to affect their lives through deflecting them from their original characters. Wherefore it is said of heresies they ‘they survive by the truths they retain.’” (pp. 3-4)
And about Protestantism in particular he wrote:
The Protestant attack differed from the rest especially in this characteristic, that its attack did not consist in the promulgation of a new doctrine or of a new authority, that it made no concerted attempt at creating a counter-Church, but had for its principle the denial of unity. It was an effort to promote that state of mind in which a Church in the old sense of the word — that is, an infallible, united, teaching body, a Person speaking with Divine Authority–should be denied; not the doctrines it might happen to advance, but its very claim to advance them with unique authority. Thus, one Protestant may affirm, as do the English Puseyites, the truth of all the doctrines underlying the Mass — the Real Presence, the Sacrifice, the sacerdotal power of consecration, etc. another Protestant may affirm that all such conceptions are false, yet both Protestants are Protestant because they communicate in the fundamental conception that the Chruch is not a visible, definable and united personality, that there is no central infallible authority, and that therefore each is free to choose his own set of doctrines. (pg. 12)
So what if the Body of Christ isn’t ONE? If we aren’t united in a “visible, definable, and united personality”? Well first and probably most important we are going to be unable to effectively fulfill the Great Commission. Jesus said “I pray not only for them, but also for those who will believe in me through their word, so that they may all be one, as you, Father, are in me and I in you, that they also may be in us, that the world may believe that you sent me.” John 17: 20-21
What else does it mean? I talk to a lot of Protestants in my life and I find that no matter who I am talking to or even if I am simply reading one of those anti-Catholic websites, there are some recurring themes. Mary, the Saints, and the Real Presence. There are others but for some reason these really set fire to the hair of our separated brothers and sisters. “BUT WHAT ABOUT MARY!?” they shriek. I hear a lot about how we are worshipping Mary and the Saints and…I can hardly say it but I have heard it so often recently…the cracker. [sob] And no matter how often we Catholics say “We don’t worship Mary and the Saints.” They come back to it with a discussion the ten commandments and graven images and they might even tell you how we ELIMINATED one of the ten commandments. (Ho Kai Paulos did a very nice rebuttal of this common argument here. Thank you kindly.) Now part of the reason for these often vitriolic attacks on the Catholic faith is that when you take real worship, what Jesus said “Do this in memory of Me.” out of the picture, and begin to substitute other things and call it worship; then what Catholics do looks mighty suspect (more…)