Absolution
Absolution is the word by which the priest, in the name of Christ, remits his sins to the penitent, the one who has just confessed them. The word comes from the Latin absolvere, to loose: absolution looses the sinner from the bond that sin had tied in him. It is the central act of confession, the moment when forgiveness is effectively given.
A word that truly looses
By absolution, sins are really remitted: the word of the priest is the very act by which God forgives. Christ gave his apostles the power to remit sins, and this power acts for real. “Those whose sins you remit, they are remitted to them.” John 20:23 What the priest looses on earth, God holds as loosed in heaven. “Whatever you loose on earth will be loosed in heaven.” Matthew 18:18
It is Christ who forgives
The priest forgives in the place of Christ, as his ambassador, by a power he holds from the Lord. “It is in the name of Christ that we serve as ambassadors.” 2 Corinthians 5:20 This is why, lending his voice to the Lord, he declares: “I absolve you of your sins, in the name of the Father, and of the Son, and of the Holy Spirit.” The one who forgives, by this mouth, is Christ himself.
What man brings, what God gives
It is God who forgives, by absolution; the regret of man disposes the heart to receive this gift. God gives it in respect of our freedom: he attaches forgiveness to sincere regret and to the avowal of faults. Absolution then bears all its fruit in the heart that is truly repentant. The act of the priest and the opening of the heart meet: the one bears the power of Christ, the other lets it enter.