Winning souls is like farming; we plant little seeds of Truth of God in the empty earth of empty hearts, and the great warm Sunshine of His Love and the water of His Word cause those seeds to burst forth in the miracle of new life!
Of course, we hope to win others to faith in Christ, but that's really God's job and the work of the Holy Spirit. We can only give them the Truth and show them the Lord's Love, but we can't force results and we can't make the decision for them. Whether or not they choose to believe and receive and follow that Truth is between each individual and God!
One person sows the seed, another may water it, but it is God that gives the increase! (1Cor.3:6) We can only try to prepare the ground, soften it with our tears and our prayers and sow the seed, but it's up to the individual to receive it, and only God can make it take root and grow and produce fruit!
Our job is simply to go forth bearing precious seed and to plant that seed in fertile, fruitful, receptive hearts. (Psa.126:6) We may not always see the harvest ourselves, but as long as we have faithfully done our part, we can leave the rest up to the Lord!