This question is clearly relevant in Northern Ireland. Much has been done, including activity that could never be justified, on the basis that there is a very real difference between Protestantism and Roman Catholicism. On the other hand, ecumenical 'churchmen' have toiled long to solve Ulster's problems by trying to convince us all that there is little significant difference. Who is right?
Where To Begin
If we want to get to the heart of this question, we must go back to the Bible. Surely, you say, there is no mention of either Roman Catholics or Protestants in the Bible? It is true, of course, that these terms are nowhere used. What is mentioned a great deal is the matter of our sin before God, and the one way by which sinners can be forgiven. This is where the division between Roman Catholicism and Protestantism began. It was not, in the first place, about politics, culture or nationality. It concerned the question of how sinners, such as you and I, can get to Heaven instead of going to Hell as we deserve.
The Bible is clear on this question. It tells us plainly, despite the denials of liberal churchmen, that God is holy (separate from sin) and does punish sin. "Thou art holy" (Psalm 22:3). "For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men" (Romans 1:18). The Bible tells us equally plainly that we are all guilty sinners before God. "There is none righteous, no, not one" (Romans 3:12). Christ suffered in the place of guilty sinners. "He hath poured out his soul unto death: and he was numbered with the transgressors; and he bare the sin of many, and made intercession for the transgressors." (Isaiah 53:12). Those who trust in Christ alone to save them, and only such, are forgiven. They are 'justified' (declared not guilty) by God, the Judge of all. Even the willingness to trust in Christ can come only from God. "No man can come to me, except the Father which hath sent me draw him" (John 6:44). According to the Bible, salvation is all of grace - the undeserved kindness of God.
After the time of the Apostles, many unbiblical and harmful practices found their way into the church. Above all, the gospel was gradually distorted beyond recognition. Instead of forgiveness being viewed as belonging to those who trust only in Christ and his redeeming work on the cross, an elaborate system of salvation largely through one's own efforts was put in the place of the Biblical gospel. Various errors developed, such as a human priesthood, Christ's physical presence at the Lord's Supper, penance, purgatory etc. Through these ideas, acceptance with God was no longer viewed as being only by faith in an all-sufficient Saviour, but rather through a process of purification begun in this world and completed in the 'fires of purgatory' in the next.
Darkness and ignorance of the true gospel deepened over the whole of Europe until God brought about the Protestant Reformation in the 16th century. Men who had been brought up as Roman Catholics, like Martin Luther, John Calvin and John Knox, were brought, by the grace of God, to see that acceptance with God could never be earned by any merits of their own. They were 'born of the Spirit' and thus made willing to trust in Jesus Christ alone for salvation. They protested against Roman Catholic teaching and became known as 'Protestants'.
Where It Will End
The Bible is emphatic that any sinner who seeks acceptance before God on any other basis than what the Lord Jesus has done in bearing the guilt of sin on behalf of sinners; will never be accepted by God. Thus the Apostle Paul desired to be "found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith." (Philippians 3:9). He speaks severely against false teachers who taught a gospel of self-salvation, calling it "another gospel" (Galatians 1:6). Christ's offering of himself is not to be, and need not be, repeated; "So Christ was once offered to bear the sins of many" (Hebrews 9:28). We must trust in this Saviour, coming to him as those who have nothing with which to earn or buy acceptance with God. "Ho, every one that thirsteth, come ye to the waters, and he that hath no money; come ye, buy, and eat; yea, come, buy wine and milk without money and without price" (Isaiah 55:1). At the last judgment, the divide will be between those who have trusted Christ alone to save them and those who have not. "He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him" (John 3:36).
Where You Fit In
It is clear that to trust in a man-made priesthood, sacraments and our own endeavours leads not to forgiveness and peace with God, but to eternal condemnation. But are you any less liable to the judgment of God if you trust in the name 'Protestant', your decent life-style, your lodge-membership and church-going? All forms of self-righteousness, whether allegedly Protestant or Roman Catholic, lead to Hell. Only Christ can save and if you will not trust only in him, you will bear the punishment of your sins forever. Don't trust in your Protestantism, but in the Saviour our Protestant Reformers trusted; Jesus Christ. And if you are a Roman Catholic reader, we say to you in love, you too must trust in Jesus Christ. All kinds of sinners must trust the only Saviour, who said, "I am the way, the truth, and the life: no man cometh unto the Father, but by me." (John 14:6).