The sacrifice won forgiveness of sin and reconciliation with God. The sacrifice was a demonstration of forgiveness of sin and reconciliation with God as it definitively showed God’s willingness to prove His love for man despite man’s sin. That was God hanging on the cross. If man’s “distorted image” of God, which the Catechism says man conceived of at the Fall, included a God who was angry, distant, and otherwise aloof in His power and superiority, the cross proves just the opposite. He’s on man’s side, wanting only the very best for him, even as man ‘hated Him without reason’ as Scripture teaches. God is trustworthy, good, merciful, kind, patient, and true. He’s humble, even, amazingly. He seeks to serve man, loving him lavishly. His purpose is to turn man back to Him. What Jesus “bought” was communion with God as He reveals God to us, as He gives us, individually, the “knowledge of God” that was lost or forfeited at the Fall, causing man to be lost as a result.
This communion with God, ‘apart from Whom we can do nothing’, John 15:5, is the heart and soul of Christianity. It constitutes man’s justice, the right order of things. It, alone, can restore and ensure man’s moral integrity, his wholeness, his holiness; man was never created to sin in the smallest way and yet he cannot refrain from it permanently if autonomous from God, the ‘exile’ we’re born into now.
This communion is the fulfillment of the New Covenant prophecy of Jer 31:33-34; it’s the direct, individual knowledge of God mentioned in verse 34, making verse 33 possible where He now does a work in us, of justifying us by ‘putting His law in our minds and writing it on our hearts’.
This communion is the indwelling of the Trinity. It’s the finding and saving of man, as man is ready. It’s sanctifying grace, the grace to finally fulfill the greatest commandments, to love God with our whole heart, soul, mind, and strength and our neighbor as ourselves. And this love excludes sin by its nature.
It’s all a matter of the will, aided by grace. Consider the following teachings of the Church on man’s freedom:
1731 Freedom is the power, rooted in reason and will, to act or not to act, to do this or that, and so to perform deliberate actions on one’s own responsibility. By free will one shapes one’s own life. Human freedom is a force for growth and maturity in truth and goodness; it attains its perfection when directed toward God, our beatitude.
1732 As long as freedom has not bound itself definitively to its ultimate good which is God, there is the possibility of choosing between good and evil, and thus of growing in perfection or of failing and sinning. This freedom characterizes properly human acts. It is the basis of praise or blame, merit or reproach.