Is There an Intention Attached to a Prayer?

According to common theological understanding, in order to obtain an indulgence, you have to have the intention to gain it. It is commonly also understood that the intention does not have to be conscious. Of desire can apply to people who don't even know they need to be baptized. And so if some theologians could work for indulgences from a person's state of heart, then god knows what he wants and will grant it.