18 “You, then, listen to the parable of the sower: 19 When anyone hears the word about the kingdom and doesn’t understand it, the evil one comes and snatches away what was sown in his heart. This is the one sown along the path.
In verse 15 of the same chapter, Jesus gives the reason which was prophesied by Isaiah why the people didn’t understand God’s Word, their hearts have become calloused. When people reject your message about Jesus, is not because you weren’t as convincing but because Satan got to them first and convinced them of the lie and made their hearts cold towards the truth. We see this in 2 Corinthians 4:4 which says, In their case, the god of this age has blinded the minds of the unbelievers so they cannot see the light of the gospel of the glory of Christ, who is the image of God.
Don’t give up on the person because the Holy Spirit is the only one that can soften a hardened heart, no amount of persuasion on our part will ever have that impact. Our obligation is to tell them the truth about Jesus death and resurrection and the Holy Spirit’s position is to open up their hearts so that He can give them understanding and be saved.