Relics are physical objects associated with saints or with Christ Himself, venerated as tangible connections to holy persons. The Church classifies relics into three categories: (1) First-class relics — body parts of a saint (bones, hair, blood). Every consecrated altar in a Catholic church contains a first-class relic. (2) Second-class relics — objects owned or used by a saint (clothing, books, rosaries). (3) Third-class relics — objects that have been touched to a first-class relic. Veneration of relics is rooted in Scripture: in 2 Kings 13:21, a dead man came back to life upon touching the bones of the prophet Elisha; in Acts 19:11-12, handkerchiefs that had touched St. Paul healed the sick. The Church does not teach that relics have magical power in themselves; rather, God works through them as instruments of grace. The buying and selling of relics (simony) is strictly forbidden by Church law. Relics must be authenticated by Church authorities before public veneration.