“For no good tree bears bad fruit, nor again does a bad tree bear good fruit, for each tree is known by its own fruit. For figs are not gathered from thornbushes, nor are grapes picked from a bramble bush. The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks.The nature of a tree determines or defines the kind of fruit it produces.
Jesus said in Luke 6:43-45 that the tree is known by its fruit. So, for our fruit to change, our nature must change.
One false doctrine floating around out there is that we can change ourselves. But the Bible says, “Can the Ethiopian change his skin or the leopard his spots? Then also you can do good who are accustomed to do evil.”
Ezekiel 36:25-27 says ”I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols I will cleanse you.26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.”
And in John 3:37 “Jesus answered, “Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. 6 That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. 7 Do not marvel that I said to you, ‘You must be born again.’
We need a new heart. We need to be born again. We need a new nature. We can’t bear good fruit without being born again. God looks deep within us at our desires. God changes our desires by giving us a new heart.