At what age does a baptized person (specifically, a child baptized as an infant) incur the obligation to attend Mass on Sundays?
The obligation of worshiping God is imposed on all mankind by the natural law. However, the obligation to participate in Sunday Mass, as imposed by Church law (CIC 1247) is ecclesiastical law. Ecclesiastical law generally is binding on all Catholics at least seven years of age who possess sufficient use of reason. The Code of Canon Law states, "Merely ecclesiastical laws bind those who have been baptized in the Catholic Church or received into it, possess the efficient use of reason, and, unless the law expressly provides otherwise, have completed seven years of age" (CIC 11).