What is the balance between our part and God's part in conversion?
Believers must do their part by opening the Scriptures and presenting the gospel, but they cannot force belief. Conversion requires an act of God Himself, who alone opens the spiritual heart, as He did for Lydia. People are blinded by Satan, so only God can remove that blindness and enable faith.
Les teaches that when dealing with people, we have to do our part and open the Scriptures, but we cannot stuff it down their throat or force them to believe. That takes an act of God Himself. In Acts 16:14, Lydia worshipped God and was religious, yet she was still lost. Paul and Barnabas did not open her heart; the Lord did. Likewise, the god of this world blinds unbelievers, and unless God strips away that blindness, even we are helpless. Our part is faithful presentation; God's part is opening the spiritual heart.