Ok, from my understanding, as well as the way this all makes most sense to me, is that the Spirit stirs and draws and enables us to believe, He "establishes cooperation between God's grace and man's freedom", is one way I've heard it taught. And yet it continues:
"When God touches man's heart through the illumination of the Holy Spirit, man himself is not inactive while receiving that inspiration, since he could reject it; and yet, without God's grace, he cannot by his own free will move himself toward justice in God's sight."
We're invited to conversion according to this same teaching. So the Spirit doesn't just overwhelm us and drop a new heart of flesh in us; He's always a gentlemen, seeking to finally guide us into making the right choice- and continuing to do so. And other factors are involved as well. The experience of this life, a life of exile from God, essentially lacking His direct control in our moral world with all that entails including the experience-or knowledge-of both good and evil, the good inherent in God's creation alongside the sin and evil that we're all exposed to and participate in here on earth due to man's will reigning, and due to death, the wages of sin, can teach us to hate and to shun evil in favor of good, the ultimate Good being God, Himself. It's always been about the human will, which is the reason for the centuries long "education" of man beginning immediately after the Fall, through God's dealings with His chosen people, and up to the advent of Christ when the full and final revelation was made. We just don't have to choose the light; we can remain in darkness instead; we can continue to prefer ourselves to God, another teaching describing Adam's sin of disobedience.
