“Verily, verily I say unto thee, except a man be born again, he cannot see the kingdom of God.” Nicodemus saith unto Him, “How can a man be born when he is old? Can he enter the second time into his mother’s womb, and be born?” Jesus answered, “Verily, verily I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. That which is born of the flesh is flesh; that which is born of the Spirit is spirit. Marvel not that I said unto thee, ye must be born again.” John 3:3-6
If you know someone who’s not a Christian, don’t try to argue with them. Nobody was ever argued into the kingdom of Heaven. Anything someone can argue you into, you can be argued out of. The problem is, they cannot see. Would you scold a blind man for not seeing? On the other hand, a blind man would be foolish to say there’s no light just because he cannot see it.
There is light, but man needs more than light. He needs sight. “...Except a man be born again, he cannot see the kingdom of Heaven.” He may have 20/20 sight, but spiritually he’s blind. “Having their understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart” (Ephesians 4:18). The eyes may be fine, but the heart is blind.
There are people you have shared the Gospel with—perhaps even members of your own family—but they haven’t a clue as to what it’s all about, and they never will, until the Holy Spirit opens their understanding.
It takes more than preaching to get somebody saved; it takes the work of the Holy Spirit of God. Pray: “O God, open the eyes of those who have been blinded, that the light of the glorious gospel of Jesus Christ, who is the image of God, might shine unto them.” (2 Corinthians 4:4). Before I ever preach, I get on my knees and pray, “O, God, for those who need Jesus Christ, give them sight.”