What is an “Indulgence”?

Let's start with the Catechism of the Catholic Church's definition, and then we'll break it down a bit.

The Catechism of the Catholic Church explains, “An indulgence is a remission before God of the temporal punishment due to sins whose guilt has already been forgiven, which the faithful Christian who is duly disposed gains under certain prescribed conditions through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints.” (Paragraph 1471) 

Let’s explain. Our sins have effects– some of these effects may be eternal (if we die in the state of unforgiven mortal sin, we merit hell) and some effects are temporal. After all, even the “smallest” venial sins change us (they draw us away from God, make us less like Christ) and affect those around us. Even after we go to the Sacrament of Reconciliation and are forgiven our sins and freed from the eternal punishment we deserve, we still have to atone for our sins. We need to be purified of those temporal punishments, the unhealthy attachments and ways we’ve hurt ourselves, others, and God. This purification can be done in Purgatory, but it can also be done here on earth: by offering up our sufferings and by becoming more like Christ in acts of charity and prayer.

To be clear, an indulgence is not: permission to commit a sin, something you pay for, a “get out of jail free card,” or a way to earn God’s love (which isn’t earned, but is freely given). Rather, indulgences are graces given through the Church as she opens “the treasury of the merits of Christ and the saints.” The Church encourages us to do works of devotion, penance, and charity. For example, there are indulgences attached to spending time in mental prayer, praying the Stations of the Cross, or, the corporal and spiritual works of mercy.

Along with the act that the indulgence is attached to (like walking through the Holy Doors in a pilgrimage of penance and spirit of conversion), the penitent must also go to the Sacrament of Confession, receive Holy Communion, and pray for the intentions of the Holy Father while striving to be detached from sin.

Some indulgences are partial (removing part of the temporal punishment due to sin) and some are plenary (removing all of the temporal punishment due to sin). An indulgence can also be applied to a loved one who is in purgatory.