One of the most well-known statements in Acts 16 and the conversion of Lydia and her household. In verse 14, the text says, “The Lord opened her heart to heed the things spoken by Paul.” Lydia is the only hearer mentioned in the text as having her heart opened, yet all the women present are spoken of as being baptized following the teaching of Paul. Question: did the Lord operate directly on Lydia’s heart, or did He use means, that is, working indirectly through some medium?
In John 16, Jesus promised to send the Holy Spirit, who would convict the world of sin, righteousness, and judgment (v 8). In John 17, Jesus spoke of having given the apostles the word they would preach to the world (v 8, 18). Jesus also spoke of all who would believe in Him through the apostles’ words (John 17:20).
In Acts 2, the apostles preached the gospel, that message given to them by the Holy Spirit (v 4). In verse 36, Peter concludes his opening salvo with this statement, “Therefore let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ” (v 36). In response to the preaching of the word, Acts 2:37 says, “Now when they heard this, they were cut to the heart, and said to Peter and the rest of the apostles, ‘Men and brethren, what shall we do?’” In this case, we see the preaching of the word of God as the means by which men are convicted in their heart by the Holy Spirit.
Finally, in Acts 7:51 Stephen accused his Jewish audience saying, “You always resist the Holy Spirit; as your fathers did, so do you.” Were they in a literal battle against the Holy Spirit (and winning), or were they resisting the words of Stephen given by the Holy Spirit?
So then, as it was the Spirit-given word of God preached that convicted the Jews at Pentecost, and as it was the Spirit-given word of God preached that Stephen’s audience resisted, it was the Spirit-given word of Paul that opened Lydia’s heart and the hearts of those women with her.
God does not override humanity’s free will or miraculously intervene to save those who have no desire to be saved. This is why the Gospel is God’s power to save as it reveals God’s righteousness (Romans 1:16-17).