When Adam was created He had his nature, which was able, had the capacity to sin.
After Adam sinned, his nature was corrupted when his "eyes were opened."
Thus our "old man" nature is the same corrupted nature of the fallen Adam.
So a pure heart can sin, but a corrupted heart has a hard time not sinning.
That's not what it says. It says to one group it is given to know certain things, and to another it is not given. One group is given a gift, the other is not. You say it's because one group has behaved better than the other, and therefore merited it. God always and ever says one is given something because of election, and not because one has done either good or evil.
So the choice to sin isn't from a corrupt heart? That choice comes from a free and pure heart, and only AFTER the sin is committed one's heart is corrupted?
A good tree cannot bring forth evil fruit. Adam was created good, but not incorruptible. Corruption had to set in before he would entertain a disobedient thought.
From the heart of a being, either Adam/satan, who were created wi/o sin natures in them, innocent, both willfully chose to diobey and rebel against their Creator!
It did in satan so it can in man also.
Eze 28:13-15
Thou hast been in Eden the garden of God; every precious stone [was] thy covering, the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle, and gold: the workmanship of thy tabrets and of thy pipes was prepared in thee in the day that thou wast created.
Thou [art] the anointed cherub that covereth; and I have set thee [so]: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire.
Thou [wast] perfect in thy ways from the day that thou wast created, till iniquity was found in thee.
If I were to answer, I would say that Adam was "good" but was not "perfect".
He was innocent, but not without the potential to rebel (sin).
It appears that all created beings were endowed by these properties. (Angels and Humans)
He was made good and perfect, but not incorruptible. Corruption is a passive thing, like rust on iron. It's something that happens. We can answer what corrupted Adam later. The question was, did Adam's sin come from a good and pure heart, or one that had been corrupted?
If Adam's heart was corrupted before he sinned, wouldn't that mean that the fall happened before he sinned?
Are you saying he was unsaved before he sinned?
When did he fall?
Before or after he sinned against God?