Lambeg, near Belfast where I was reared, was almost 100 per cent Protestant. I went to Protestant schools. I played Protestant sports like rugby and cricket. As a family we voted as Protestants, for a Protestant parliament for a Protestant people.
There may have been Roman Catholics in Lambeg but I certainly didn't know any. There was nothing unusual about my upbringing in Northern Ireland in the 1950s and 1960s.
It was in this context, in a good Christian home and while attending a sound Presbyterian church, that I responded as a child to the invitation to know Jesus as my personal Saviour and Lord. In those days, there were two things about which I was convinced.
The first was that being a Protestant didn't make one a Christian and the second was that being a Roman Catholic meant you definitely were not. A real Christian was someone who had been "born again" and had responded to the Gospel by receiving Jesus as saviour and Lord.
I didn't know any Roman Catholics but we knew about them. They were not to be trusted - for their loyalty was to another country, the Irish Republic. They were liable to be unemployed, either because they were lazy or because, due to their having such large families, it was in their interest because of social benefit, not to work. They were not as clean and tidy as us - hence the common expression, "Wash your face, clean yourself up and make yourself a bit more Protestant looking."
But most of all they had a religion which was as deviant and heterodox as any weird sect, like the Mormons or the Jehovah's Witnesses. This was all reinforced by fiery preachers who would unveil Jesuit conspiracies.
Lucan, near Dublin, where I now live and minister, is predominantly Roman Catholic. Fifteen years ago I left Northern Ireland and came to what the prophet Jonah would have called his Nineveh.
God had called me to work among people who, in terms of my past, were culturally, politically and religiously alienated from me. They were different. The truth was, I had no idea how to begin this ministry. What is a Reformed Church meant to do - try and make everybody Presbyterian? How was I to relate to a culture and sub-culture of which I was totally ignorant?
God's answer to my need was outrageous and, on his part, quite mischievous. During my second week in Lucan, I had cause to visit a school in the next village. The school was Colaiste Ciaran in Leixlip. We had a few children from my church in attendance there. When I entered the staff room I was warmly greeted by the Roman Catholic chaplain. He sat me down and within a few minutes he began to tell me his story.
It was, in the language of my upbringing, a testimony to the saving grace of God. He related how on one Good Friday he had cried out to God for mercy and invited Jesus Christ to be the Lord of his life. The result had been a radical change in perspective and behaviour.
I had heard many testimonies like this before but not from a Roman Catholic priest. However I responded it was obviously with excitement and delight. In fact, Father Dermot O'Gorman (that was his name) came to my house a few days later and asked if we could meet together since we obviously shared something that he had difficulty sharing with some of his fellow-priests.
So Dermot and I began to meet every Monday at 4 p.m. in my home. We read and studied Scripture. We prayed for and encouraged each other. I had discovered not only a priest who was my brother in Christ, but that God, in his amazing providence, had so arranged our lives that a member of a sacred order from Kilkenny should become a "Barnabas" to a Presbyterian from Lambeg. This was so that I might be better equipped to minister in a Roman Catholic context.
My encounter with Father Dermot O'Gorman has been repeated on numerous occasions with various clergy and lay folk from the Catholic community.
If these testimonies are evidence of real faith in Christ, then whatever our theological differences, these Roman Catholic believers are justified by faith alone and so are our brothers and sisters in Christ.
In Paul's Letter to the Galatians he saw this doctrine as vital for Christian fellowship and freedom. The Jewish Christians from Jerusalem had come down to Galatia and were fearful that Paul's message of justification apart from the work of the law, would undermine the traditions and identity of their Jewish inheritance.
The social and peer pressure on many Presbyterians, particularly in Northern Ireland, is akin to that experienced by the apostle Peter in Antioch, as Paul records in his Letter to the Galatians. Peter knew and believed the gospel of grace but, for fear of what others would think of him, he withdrew from fellowship with the Gentile believers because they did not conform to the practices of Judaism. Paul is so outraged by this he confronts Peter face to face on the issue.
Many evangelicals within the Reformed Church would not deny the reality of the faith of these genuine Catholic people but are hesitant to embrace them as fellow-believers for fear of what other Protestants would say or think. Some have gone further and have rewritten the gospel by suggesting that faith alone is not enough for Roman Catholics.
They must (they say) be able to articulate clearly the Reformation doctrine of justification and be willing to leave the Catholic Church before they can be accepted as fellow-members of the body of Christ. This, according to Paul, is a different gospel.
It is therefore, on the material principle of the Reformation, that a person is justified by faith alone and for the sake of the gospel that I, as a Presbyterian, unequivocally accept and affirm with joy and enthusiasm these Roman Catholic believers as my brothers and sisters in Christ.
This article is taken from the book Adventures in Reconciliation, recently published by Eagle Books, price £5.99 (£4.99 sterling).