A plenary indulgence, applicable only to the holy souls, may be gained once in any church either on All Souls' Day, on the preceding or following Sunday, or on the feast of All Saints, on the usual conditions, viz: a visit to a Church where the Our Father and Creed are recited, Sacramental Confession, Holy Communion and prayer for the Holy Father's intention. Those who visit a cemeterybetween 1st and 8th November and pray for the faithful departed, may obtain a plenary indulgence, applicable to the holy souls (and at other times a partial indulgence).The conditions to obtain a plenary indulgence are the following:
1. The faithful must receive the sacrament of confession, either eight days before or after the act is performed.The Catechism of the Catholic Church explains about indulgences:
2. Receive Holy Communion on that day.
3. Recite prayers for the intention of the Holy Father (In this case an Our Father and a Creed)
4. Absence of attachment to mortal or venial sin (I find this part incredibly sanctifying for the one attempting to obtain the indulgence)
It is necessary to understand that sin has a double consequence. Grave sin deprives us of communion with God and therefore makes us incapable of eternal life, the privation of which is called the "eternal punishment" of sin. On the other hand every sin, even venial, entails an unhealthy attachment to creatures, which must be purified either here on earth, or after death in the state called Purgatory. This purification frees one from what is called the "temporal punishment" of sin. These two punishments must not be conceived of as a kind of vengeance inflicted by God from without, but as following from the very nature of sin. A conversion which proceeds from a fervent charity can attain the complete purification of the sinner in such a way that no punishment would remain.The forgiveness of sin and restoration of communion with God entail the remission of the eternal punishment of sin, but temporal punishment of sin remains. While patiently bearing sufferings and trials of all kinds and, when the day comes, serenely facing death, the Christian must strive to accept this temporal punishment of sin as a grace. He should strive by works of mercy and charity, as well as by prayer and the various practices of penance, to put off completely the "old man" and to put on the "new man." (1472, 1473)