The Westminster Confession of Faith in Plain Language1. God created humans with the natural ability to do whatever they want to do. He did not build anything into their nature that forced them to do either good or evil.
2. In the days when Adam (who stood in for all humans) was innocent of sin, nothing kept him from obeying God—he was free to do what he wanted to do. If he wanted to do what pleased God, he could do it. But he could also sin if he wanted to, and if he did, he could lose the freedom to do what pleased God.
3. So, when Adam chose to sin, he and all humans completely lost any desire or ability to do what pleased God. Their nature changed—they were now opposed to doing good, because their ability to do good was dead in sinfulness. They had no power in and of themselves to change back. They did not even know how to begin changing themselves.
4. When God changes sinners back (which he is under no obligation to do), he changes their nature and sets them free from slavery to sin. Even though they do not deserve it, he restores their desire and ability to do good. However, because they still have some sinfulness inside them, they do not always want to do good things—they still want to do evil sometimes.
5. Humans will only be completely free to do good, with no possibility of doing evil, after they have passed from this life into glory.