<< Catholic spirituality is incarnational, meaning that it encompasses both body and soul. Catholics don't just pray with their minds, they pray with their bodies, as can be seen at Mass with the various bodily postures we assume during the liturgy (e.g., standing, sitting, kneeling). Likewise our private devotions can be incarnational. If a Catholic chooses to bury a statue of St. Joseph as a form of physical prayer to the saint for his intercession in selling a house, there is nothing wrong with that. It is not blasphemous or sacrilegious, but an authentic form of Catholic folk piety. St. Andre Bessette, as but one example, once buried a medal of St. Joseph on the site where he hoped to one day build an oratory in St. Joseph's honor, a prayer that was answered.
That said, such a practice can shade off into superstition. If the person burying the statue thinks that the very action of burying the statue (or burying the statue in a certain position) will guarantee a positive result, that is not an authentic expression of trust in God and St. Joseph's intercession, but is instead superstitious.
It should go without saying that it is all the more superstitious for a non-Christian to take up the practice of burying a statue of St. Joseph simply because there is an assurance that the act will "work." It cannot be called a form of Christian prayer for someone who is not a Christian to engage in the external act alone absent any kind of Christian faith. Of course, culpability for superstition can be mitigated by a lack of knowledge and a willingness to treat a Christian devotional item respectfully (as was the case with my friend's relatives), but it is still a more clear-cut case of superstition when a non-Christian buries a statue of St. Joseph in hopes of gaining a house. >>
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