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The Rosary of the Blessed Virgin Mary is the most heavily indulgenced prayer that laymen can say.
There are indulgences spelled out for just about everything having to do with the Rosary. The Church did this to gently encourage the faithful not to introduce abuses that would lead to corruption and make the Rosary eventually into something other than the Rosary. We can see how innovation has destroyed the Newmass, and the same thing would happen to the Rosary if there were no structure and indulgence rules.
There are indulgences for:
~ Holding the rosary beads while praying.
~ Moving your fingers from one bead to the next - one indulgence for each bead.
~ Making the sign of the Cross at the beginning, holding the crucifix of your blessed rosary.
~ If you're in a group, such as a car, and you're driving, you don't have to hold the rosary beads since your hands are needed for the steering wheel. Someone else in the car can hold the beads and everyone gets the indulgence for holding beads and moving between beads.
~ Each of the prayers carry an indulgence: the Apostle's Creed, each Our Father, each Hail Mary and each Glory be. I don't know about the Fatima Decade prayer. Perhaps there was an indulgence but I suspect not because then there would be one standard Latin version and what we have is at least 4 Latin versions in circulation. But Our Lady asked for this prayer, therefore, we say it. It's her Rosary, after all.
~ One Third of the Rosary is the shortest Rosary that is indulgenced, and that consists specifically of either the 5 Joyful, or the 5 Sorrowful, or the 5 Glorious Mysteries. (Note: the introduction of the 'luminous' mysteries was never given any indulgence of any kind, and only the Joyful, Sorrowful and Glorious Mysteries are given as indulgenced Rosary prayers.)
~ You get two Rosary indulgences for saying either the Joyful and the Sorrowful, or the Sorrowful and the Glorious, or the Glorious and the Joyful, and they are customarily said in that order, but that is not necessary for the two indulgences, that is, you can reverse the order of the two in any pair.
~ You get three Rosary indulgences, or, that is, a "complete" Rosary, for praying all 3 groups of Mysteries in one day. You can do this as often as you like in any one day and you continue to get more corresponding indulgences.
~ When you pray the Rosary with a group of people, each person in the group gets the indulgences of the entire group. Therefore, if you are 5 people you each get 5 Rosary indulgences, or 25 total. Everyone in church who prays a Rosary together gets the indulgences of however many people there are. So if 342 people show up for a Requiem Rosary, each person (presuming they're all in the state of grace) gets 342 Rosary indulgences that day.
~ You can pray one decade, and then pause for a few minutes, then pray another decade, and pause, etc., and you still get the Rosary indulgence, so long as you finish the decade before undue time goes by, and so long as you get all 5 done before excessive time passes and it needs to be finished in one day.
~ You get an extra indulgence for praying the Rosary in front of the Blessed Sacrament. In chapels now where the tabernacle is removed to a separate room, this confuses the issue, because the people praying the Rosary might not be aware of the presence, or they might have no regard for it because it is forgotten over there, or perhaps the priest also forgot about it and there are no hosts inside. So, in such cases, whoever is in charge of the Rosary should ask the priest in advance if he can make sure there is at least one host in the tabernacle, and the people should be reminded that they are saying the Rosary in front of the Blessed Sacrament.
~ There are special days for additional indulgences, such as praying the Rosary on the Feast Day of the Holy Rosary, October 7th, or at a gravesite during the month of November, the Holy Souls.
~ You can get a special indulgence for adding a few certain prayers for the Holy Father at the end of the Rosary (the indulgence says "for the intentions of the Roman Pontiff" but that was before post-concilar papal problems, so we're probably better off just praying for the pope after all).
~ You are required to say the words of the prayers (or half the words if in a group of two or more the halves are shared alternatively) while meditating on the associated Mystery for that decade. If you can only think about the Hail Mary, or else the Presentation in the Temple for example, but have a lot of trouble thinking about both at the same time, that's okay, but you do need to trade off, then, at least once during the decade and more often if possible. Ultimately, you should learn to go back and forth between thinking of the Hail Mary and thinking of the Presentation two or more times during each Hail Mary. In that way, your mind will not wander so much to worldly matters while you pray. But keep in mind, it's okay to think about worldly matters during the Rosary, so long as you are ALSO thinking about the Rosary. Your mundane affairs should not be foremost in mind all the time, because pretty soon you'll say, "Why am I saying all these words when I'm not thinking about the Rosary?"
~ There is another indulgence for praying the Rosary in an oratory, even without the Blessed Sacrament present.
~ All indulgences presume you are in the state of grace. If you are not in the sate of grace, praying the Rosary won't hurt you, but the graces will not be entirely effective until you make a good Confession.
There may be more of these, because I am just going by memory here. I might have made a mistake. These should be checked against the Raccolta, for example.
The only other activity that laymen can do with greater efficacy for indulgence is to assist at Mass and receive Communion worthily. Stations of the Cross are another indulgenced prayer but they are no more so than the Rosary, plus, there are not nearly so many specific provisions, only that you move from one station to the next, say some devotional prayers, and the stations must be erected or blessed by the local bishop. But there are not specific indulgences for each individual part like there is with the Rosary indulgences.
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