What we do is a result of what we desire.
Because they hated knowledge
And did not choose the fear of the Lord,
Would have none of my counsel
And despised all my reproof,
Therefore they shall eat the fruit of their way,
And have their fill of their own devices. (Prov 1:29-31, ESV)
To understand this section, we must understand what the Bible teaches about desire. In particular, what we do is a result of what we desire. 2 Peter 3:3 states that those who scoff at the truth of God’s Word are simply “following their own sinful desires.” Jesus said that “the good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil,” just like different kinds of trees each produce their own kinds of fruit (Luke 6:43-45). This teaching means that we do certain things because we desire certain things.
For example, someone yells in anger because he doesn’t get the respect he wants from others. Someone else looks at pornography out of a desire for comfort, escape, control, or pleasure. Another person says foolish or untrue things because she desperately wants people to like her. In all our actions, what we do is a result of what we desire.
Now when someone believes in Jesus, the Spirit of God takes up residence within him, giving him new godly desires. Galatians 5:16-26 provides a good explanation of this person’s situation. God’s Spirit intercepts his slavery to the old “desires of the flesh” (Gal 5:16). Those old desires won’t give up easily, though, so a battle ensues over which desires will hold supremacy in his heart (Gal 5:17). The presence of such inner turmoil is a sign that he is growing in grace, even if it feels to him like he’s a miserable failure. Thus, he must be reminded constantly that he is free from the penalty of God’s law because Jesus died for him (Gal 5:18). The more he gives in to the old desires, however, the more he will commit sinful actions (Gal 5:19-21). The more he trusts in Jesus through his Spirit, the more he will demonstrate godly character and behavior (Gal 5:22-24). Over time, the Spirit gains more and more ground over the flesh, and the old desires decrease in frequency and power (Gal 5:24-26).
This process is what we normally call Christian growth, or sanctification, and it’s not easy.