Quoting from an article in the National Catholic Register (April 26, 2019): "According to Robert Stackpole, the director of the John Paul II Institute of Divine Mercy, an apostolate of the Marian Fathers of the Immaculate Conception, “The most special grace promised by our Lord for Mercy Sunday is nothing less than the equivalent of a complete renewal of baptismal grace in the soul: “complete forgiveness (remission) of sins and punishment.” (More explanation here.)
Did you know that when you gain a plenary indulgence you can ask Our Lord to apply it to a soul who may be in purgatory? Can you tbink of a greater gift?
To gain the Divine Mercy Indulgence, receive the Sacraments of Reconciliation and the Holy Eucharist within a week or so of Divine Mercy Sunday, and add the following "work":