Verses 15 and 16 go on to tell us what happened in Paul’s conversion. On the road to Damascus (Acts 9) Paul came face to face with Jesus Christ. That encounter had much more to it than meets the eye!
It immediately involved Paul in having to face the fact that he was wrong! (He had probably known for a long time that he was wrong, but was too proud to admit it. See Acts 26: 14.)
Suddenly the reality of Christ burst upon him. The Son of God was revealed to him, and at the same time in him. Within the next few days he had become a new person. He knew that his sins were forgiven and he had received the gift of the Holy Spirit (see Acts 22:15 and Acts 9:17).
From these two verses, note again that it was God who revealed Himself to Paul. But also notice another important truth. God chose Paul before he was even born! Look at the way he puts it in verse 15:
"God ‘set me apart before I was born’; God ‘called me through his grace’; God ‘was pleased to reveal his Son in me’."
This is true for every believer. Every Christian has been set apart by God before birth, has been called by Him at the time, and has had Christ revealed to him or her. This should be fantastic encouragement to us! God does it all!
The truth is, if He didn’t do it all, we’d never come to faith in Christ. If it were not for the fact that God chooses us, then we would never come to know Him. Left to ourselves we would never choose Him. Take a look at John 15: 16, and compare that with John 6:44.