Well, Michael, I can't explain it, but that doesn't prove you were regenerated to believe. Who can understand human nature? I got saved when I was 11, and it was really the very first time I had heard a powerful preaching of the gospel. My family was not religious whatsoever and rarely attended church. I had been a few times when I was very young and knew Jesus was God's Son and believed that. But until a neighbor invited me to church and I heard a powerful sermon on sin and hell I never thought of myself as a lost sinner, in fact I had been taught that good people go to heaven and bad people go to hell (works).
Paul himself resisted the Holy Spirit. He was there when Stephen preached to the Jews. As you know, they became so angry they knashed their teeth and stopped their ears. They rushed upon him and dragged him out of the city and stoned him. They laid their garments at Paul's (Saul) feet.
Acts 7:58 And cast him out of the city, and stoned him: and the witnesses laid down their clothes at a young man's feet, whose name was Saul.
As you might know, Paul (Saul) became a determined persecuter of the Christians. He threw many in prison and I believe put some to death. Christians were fleeing Jerusalem for their lives. That is why Paul went to Damascus, to capture Christians who had fled there for safety. And it was Paul especially they were trying to escape.
Acts 8:1 And Saul was consenting unto his death. And at that time there was a great persecution against the church which was at Jerusalem; and they were all scattered abroad throughout the regions of Judaea and Samaria, except the apostles.
And even when the Lord appeared to Paul, I believe there was still some resistance there.
Acts 9:3 And as he journeyed, he came near Damascus: and suddenly there shined round about him a light from heaven:
4 And he fell to the earth, and heard a voice saying unto him, Saul, Saul, why persecutest thou me?
5 And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks.
6 And he trembling and astonished said, Lord, what wilt thou have me to do? And the Lord said unto him, Arise, and go into the city, and it shall be told thee what thou must do.
Notice the strange question Paul asked the Lord when he asked "Who art thou Lord?". Now why is that strange? Because the Lord had just asked, "Saul, Saul, why persecutest thou me?"
Now, don't you think Paul was quite aware who he was persecuting? Of course he was. So, he was in a bit of denial here if you ask me.
And that he was still resisting is shown by what Jesus answered, "I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks."
Paul was still resisting, Jesus said he was kicking against the pricks. But now Paul had heard from Jesus's own mouth his name. What could he do now? It was either continue to resist Jesus or submit. And fortunately he submitted, for the next thing he said was, "Lord, what wilt thou have me to do?". I personally believe this is the very moment Paul was saved, for the first time he confessed that Jesus was the Lord, and asked what Jesus would have him do.
But notice, even in this case Paul first heard the word of God. It was not the light from heaven that brought him around, it was the words of Jesus.
And Paul did not receive the Holy Spirit until three days afterward.
Acts 9:9 And he was three days without sight, and neither did eat nor drink.
Only after three days did Ananias come and lay hands on him and he received the Spriit.
Acts 9:17 And Ananias went his way, and entered into the house; and putting his hands on him said, Brother Saul, the Lord, even Jesus, that appeared unto thee in the way as thou camest, hath sent me, that thou mightest receive thy sight, and be filled with the Holy Ghost.
So, why do some men resist more than others? I can't say for certain, but I think personal pride is the biggest problem. It is a known fact that the vast majority of Christians accept Jesus when very young. Why? Because children are very humble. It is only when we get older that men become filled with pride. And statistics have proven that the older a person is when they hear the gospel, the less likely they are to accept Christ.
So, I believe pride is the single biggest problem when it comes to people accepting Christ.