According to our noble Catholic tradition the buying of indulgences ie Mass or Good Intentions will help ya out of purgatory and on your way to heaven. Since Luther hit a notice into a cathedral door the Church has gotten rid of the term indulgences which are now called many a different thing. In Laois' case as in most of Ireland, would be referred to as a good work. With that in mind the reference to ST Peter is a traditional one in that it is said that he'll eb waiting at heavens gate to let the worthy in and the goats out. Seeing as most of us are not Sts and will probaby need a few prayers to get us out od purgatory this expression is used to remind those bound to the earth that them or their relatves are going to need to fork out in order to get them to the house of himself.
