The Sacrament of Baptism frees us from sin and makes us a new creation (see Catechism of the Catholic Church, No. 1213). It does not, however, take away our free will, and experience shows us we are sadly prone to fall into sin after our initial conversion. God’s mercy provides a number of remedies for such subsequent sin, principally the Sacrament of Reconciliation.
The Sacrament of Reconciliation restores the union with God that is weakened by sin, but we may still suffer a lingering need for spiritual purification. Our theology teaches us we may accomplish this purification here on earth or, after our death, in purgatory.
We call this purification “atonement,” and we accomplish it in various ways. The Catechism identifies traditional forms of prayer, fasting and almsgiving, as well as “revision of life, examination of conscience, spiritual direction, acceptance of suffering, endurance of persecution for the sake of righteousness” (No. 1435). The text also recommends frequent reception of the Eucharist (No. 1436).
The value of atonement is its power to unite our pain with the suffering of Christ. The cross “reconciles man with God … and it heals” (No. 1990). To seek signs of the cross in our life enables us to embrace Christ’s love more intimately.