Q. Do I have to go to Confession on Divine Mercy Sunday in order to receive the Promise of Divine Mercy?

A.  No. Your sacramental Confession does not have to be made on Divine Mercy Sunday in order to receive the benefits of Jesus’ Promise, or meet the requirements of the Plenary Indulgence.  It can be made before or after Divine Mercy Sunday.

According to Church teaching: It is appropriate, but not necessary, that the sacramental Confession and especially Holy Communion … take place on the same day that the indulgenced work is performed; but it is sufficient that these sacred rites and prayers be carried out within several days (about 20) before or after the indulgenced act.

********** Our Lord’s Promise to St. Faustina is part of a private revelation that has been accepted by the Church.  But St. John Paul, during his papacy, also created a Plenary Indulgence of Divine Mercy.  While Catholics are not obligated to believe in private revelations, they are obligated to believe by faith that if they fulfill the conditions of an Indulgence, that they will certainly receive what the Pope has promised: full remission of the temporal punishment due to their forgiven sins. This explains why the Holy See “institutionalized”the Promise in the form of an Indulgence. Like creating the Feast of Mercy itself, it was inspired by a private revelation, but made effective by the authority of the Church. Conditions For Achieving the Indulgence on Divine Mercy Sunday* • A sacramental confession • Eucharistic communion • Prayers for the Pope’s intentions • Take part in the prayers and devotions held in honor of Divine Mercy, or , in the presence of the Blessed Sacrament exposed or reserved in the Tabernacle, recite the Our Father and the Creed, adding a devout prayer to the merciful Lord Jesus ( e.g. “Merciful Jesus, I trust in You.”) * It is appropriate, but not necessary, that the sacramental Confession and especially Holy Communion and the prayer for the Pope's intentions take place on the same day that the indulgenced work is performed; but it is sufficient that these sacred rites and prayers be carried out within several days (about 20) before or after the indulgenced act. Prayer for the Pope's intentions is left to the choice of the faithful, but an "Our Father" and a "Hail Mary" are suggested.--From EWTN website