Act 13:48 And when the Gentiles heard this, they began rejoicing and glorifying the word of the Lord, and as many as were appointed to eternal life believed.
In salvation what comes first, faith or regeneration? If man is spiritually dead (Eph 2:1), he cannot believe therefore regeneration precedes faith. Faith is not the cause of eternal life, it is a gift in response. Paul preached the gospel to eagerly waiting Gentiles, large numbers believed and they experienced salvation in Christ. God gave them power to believe as if to say they believed whose hearts the Lord opened (Act 16:14).
The Spirit of God does move upon the human heart to which some respond, as here and we cannot fully explain how that works. In my lack of fully grasping this mystery, I take comfort in this hymn’s lyrics “l know not how this saving faith to me He did impart, Nor how believing in His Word wrought peace within my heart. I know not how the Spirit moves, Convincing men of sin, Revealing Jesus through the Word, Creating faith in Him. But “I know Whom I have believed, And am persuaded that He is able To keep that which I’ve committed Unto Him against that day.”” It is not for me to understand, it is for me to proclaim and let Him do the saving and get all the credit.