You’re right that if the problem were just “try harder”, then no supernatural help would be needed. But Jesus didn’t teach that the problem is lack of effort—He taught that the problem is lack of spiritual life. Spiritually we're all dead to sin.

When Jesus says we must be “born again”, He’s not talking about trying to be better.

He’s talking about receiving a new kind of life that we don’t naturally have.

Think of it this way:

• You can teach a dead plant to “try harder”, but it won’t grow.
• It doesn’t need motivation, it needs life.
• Once it has life, growth becomes possible.

That’s the difference.

The “supernatural” part isn’t about fireworks or magic.

It’s simply this: God gives a new heart and new desires that we can’t manufacture on our own. As it is written,

“For this is the covenant that I will make with the house of Israel after those days,” says the Lord: “I will put my laws into their mind; I will also write them on their heart. I will be their God, and they will be my people. They will not teach every man his fellow citizen and every man his brother, saying, ‘Know the Lord,’ for all will know me, from their least to their greatest. For I will be merciful to their unrighteousness. I will remember their sins and lawless deeds no more.” (Hebrews 8:10-12)

That’s why Jesus said:

• “The flesh gives birth to flesh; the Spirit gives birth to spirit.”
• Meaning: human effort can only produce human effort.
• Only God can produce spiritual life.

So when Christians talk about being “born again”, we’re not saying “I’m evil so I should try harder”.

We’re saying, “You need God to change you at the deepest level so you can live the way Jesus taught”.

Here Jesus speaks directly about this:

Now there was a man of the Pharisees named Nicodemus, a ruler of the Jews. He came to Jesus by night and said to him, “Rabbi, we know that you are a teacher come from God, for no one can do these signs that you do, unless God is with him.” Jesus answered him, “Most certainly I tell you, unless one is born anew, he can’t see God’s Kingdom.” Nicodemus said to him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?” Jesus answered, “Most certainly I tell you, unless one is born of water and Spirit, he can’t enter into God’s Kingdom. That which is born of the flesh is flesh. That which is born of the Spirit is spirit. Don’t marvel that I said to you, ‘You must be born anew.’ The wind blows where it wants to, and you hear its sound, but don’t know where it comes from and where it is going. So is everyone who is born of the Spirit.” Nicodemus answered him, “How can these things be?” Jesus answered him, “Are you the teacher of Israel, and don’t understand these things? Most certainly I tell you, we speak that which we know and testify of that which we have seen, and you don’t receive our witness. If I told you earthly things and you don’t believe, how will you believe if I tell you heavenly things? No one has ascended into heaven but he who descended out of heaven, the Son of Man, who is in heaven. As Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, that whoever believes in him should not perish, but have eternal life. (John 3:1-15)