Here is a story of a non-catholic man who experienced the illumination of conscience:
bellsouthpwp.net/l/a/lasereye/warning5.html
Gary (not his real name) is of the Anglican faith.
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I later told him that they were starting a Perpetual Adoration Chapel at the parish of St. Louis de Montfort. He could go there and participate in the Eucharist as a Protestant by worshiping Jesus present in the Sacrament even though he could not consume the Body of Christ.
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“After about a year of worshiping the Eucharist at the Chapel, he called me one day and said. “I need to go to confession to a Catholic priest.” I told him that under normal circumstances one had to be a member of the Church in order to go to confession to a Catholic priest.
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Then he said, “I’ve had the warning.” I asked him what he meant by saying I’ve had the warning? He replied, “I’ve had the great purification as I prayed before the Eucharist, and I need to go to confession very badly.”
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I need your help. I have to have this thing called absolution.
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I have seen my soul. God has shown me my soul as He sees it. It was the worst experience I have ever had in my life, but at the same time it was the greatest experience of Love I’ve ever had.
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He explained, “It comes in three waves. The first thing I began to see was every instance in my life that I committed a serious sin since the time I was about 7 or 8 years old. Very vividly I remembered all the people who were there, the room, the scene, everything. It flashed before my eyes.” I asked him if it was like a vision. He said, “No it was like a reawaking of a very vivid memory, switching from each instance to the next. That’s what Catholics call mortal sins.” I asked him how he knew that. He answered, “Because part of the experience is infused knowledge. I was given a teaching on the Catholic Church-the one true Church- the only true Church, that the other churches are mistaken.”
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He continued, “Well, I saw all the deadly sins I committed. Then it started all over again, and I saw all of the intentional sins that are not deadly. There were occasions where I knew better than to say something bad about a person, but I was in a group and people were making negative comments about a person and putting someone down. I just went ahead and joined the conversation. Although I had a little twinge of conscience, I went ahead because everyone else was doing it. I saw every instance of that in my entire life.”
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Gary continued, “Now I will tell you the bad news and the good news. The good news for you is that you will not get wave one and wave two. You go to Mass and communion every day and confession often. But you will get wave three.” I asked him, “What is wave three?” He said, “I saw every time that I went into a Catholic Church and did not genuflect and give reverence in front of the tabernacle of the Blessed Sacrament. I would rather experience anything than what I experienced in that third wave, let alone the first two waves. No one is going to be prepared for this.”
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Gary said, “Look, I believe that if I don’t go and get this thing called absolution from a Catholic priest today, that I will be dead tonight.”
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I asked God, Please let this man make a perfect confession. He made a 1-1/2 hour confession, and he came back and is the most well balanced happiest man I know. He is now in the process of becoming Catholic.”