Man cannot believe in Jesus Christ for salvation unless God himself calls them.
We would like to think we have the capacity to believe in a God that created everything, that sacrificed His son for us, that paid the ultimate price... but we don't. We are totally depraved.
So no, I don't think preaching the gospel will convince the unregenerate to believe, but I do it so that God might call in His Elect people through my testimony.
-
Genesis 6:5: "The Lord saw how great the wickedness of the human race had become on the earth, and that every inclination of the thoughts of the human heart was only evil all the time."
Romans 3:10-12: "As it is written: 'There is no one righteous, not even one; there is no one who understands; there is no one who seeks God.'"
Ephesians 1:4-5: "For he chose us in him before the creation of the world... In love he predestined us for adoption to sonship through Jesus Christ, in accordance with his pleasure and will."
John 6:37, 44: "All those the Father gives me will come to me... No one can come to me unless the Father who sent me draws them, and I will raise them up at the last day."
Ephesians 2:8-9: "For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God—not by works, so that no one can boast."