An indulgence is a remission of our temporal punishment because of a sin whose guilt has already been forgiven. When we go to the Sacrament of Reconciliation and ask forgiveness, temporal punishment still remains. Temporal punishment is the consequence of sin that sends us to Purgatory; that is why we need indulgences to become free of punishments. The faithful can gain indulgences with the help of the church.

Visiting the Blessed Sacrament, praying the Rosary, going to Mass and doings acts of that are listed on the enchiridion of indulgences could help us remit our temporal punishment. On Divine Mercy Sunday, we can also gain plenary indulgence; plenary means "complete" or "full." This means we can obtain full forgiveness and repentance for the consequences of our sins. If all conditions are not met, then the indulgence will be partial. In a passage from the diary of St. Faustina, Jesus tells her:

“I desire that the Feast of Mercy be a refuge and shelter for all souls, especially for poor sinners. On that day, the very depths of my tender mercy are open. I pour out a whole ocean of graces upon those souls who approach the Fountain of My Mercy. The soul that will go to Confession and receive Holy Communion shall obtain complete forgiveness of sins and punishment. On that day, all the divine floodgates through which grace flows are opened. Let no soul fear to draw near to Me, even though its sins be as scarlet (699).”

Jesus promises the soul that has been to Confession and receives Communion will have plenary indulgence or be completely wiped away of stains on our soul as long as other conditions below are followed. Those stains are sins and the punishment due to sins. The special grace promised by our Lord for Divine Mercy Sunday is nothing less than the equivalent of a complete renewal of baptismal grace in the soul. We can obtain plenary indulgence on Divine Mercy Sunday on several conditions:

1. Celebrate the feast and attend Holy Mass.
2. Be in a state of grace (free from all venial and mortal sin).
3. Go to confession (20 days before, after, or during the Sunday).
4. Receive Holy Communion.
5. Place our complete trust in the mercy of Jesus.
6. Be merciful to your neighbor, Jesus tells St. Faustina: "I demand from you deeds of mercy, which are to arise out of love for Me. You are to show mercy to your neighbors always and everywhere. You must not shrink from this or try to excuse or absolve yourself from it (742)."

We can be completely cleansed with the same grace as our Baptism if we have the intention to amend our lives. The punishment is not remitted if one does not have a true act of contrition. This Divine Mercy Sunday, the Mercy of the Lord is overflowing over us, and He promised to cleanse us. If we have a sincere heart, we will obtain His forgiveness and have a way to start over in our spiritual life.