God works in the lives of men. Before we ever come into contact with them, the Lord has already been working in their hearts. Jesus told His disciples in John 4, “I sent you to reap that whereon ye bestowed no labour: other men laboured, and ye are entered into their labours.”
The Lord always works in the hearts of men through general revelation. Romans 1 and 2 say that creation and conscience instruct men about the existence of God, the power of God, the goodness of God, and the righteousness of God. Because of this working, all people know that there is a God and that He can be known.
God also works in men’s hearts through the ministry of believers. In different occasions Christians proclaim God’s Word or live a godly testimony in front of the lost, turning their attention toward the Lord. By the time a sinner repents, many believers have laid spiritual groundwork.
The Lord may see fit to use any one of us to lead a sinner to Christ. What a privilege! However, if someone were to receive Christ, we would not be the only ones who had a part: “other men laboured, and ye are entered into their labours.” Be encouraged, we can all contribute in seeing a lost person come to Christ. At the end of the day, God gives the increase.