Why is the concept of free will considered a heresy?

The concept of free will, particularly in the context of salvation, suggests that individuals have the power to choose God without divine influence. This doctrine contradicts the biblical depiction of God's sovereignty, as seen in John 1:13, which states that those born again are 'born... of God.' By promoting the idea that salvation is dependent on human choice, free will theology diminishes God's authority and the truth that salvation is wholly a work of grace. Consequently, it is crucial to acknowledge that any inclination towards God is instigated by God's action in the heart, not by human initiative.