What is the importance of Christian relics?

In Christianity, relics are objects which have a special spiritual essence about them. Many relics are bodies or body-parts of saints or things which once belonged to important religious figures like Jesus of Nazareth, the Apostles, or the Saints. Some Christian denominations do not believe in relics and reject them as idolatry, but the Catholic traditions (for the most part) believe that looking upon or touching a relic allows a person to connect with God...

In Christianity, relics are objects which have a special spiritual essence about them. Many relics are bodies or body-parts of saints or things which once belonged to important religious figures like Jesus of Nazareth, the Apostles, or the Saints. Some Christian denominations do not believe in relics and reject them as idolatry, but the Catholic traditions (for the most part) believe that looking upon or touching a relic allows a person to connect with God in a physical way. 

Any object might become a relic, but a significant number of relics are body parts from Saints or other religious persons. So what makes something like the finger of St. Thomas so special? It is believed that certain people lived in a way so Godly, or were specially endowed by God, that they carried a certain essence of "Godliness" or holiness with them. This essence is believed to be throughout the body of the person, even after death, so many bodies or parts of Saints have become important relics. The essence of holiness that I described can "rub off" onto certain objects, so items like the Shroud of Turin or a piece of clothing owned by St. Benedict are considered to have been endowed with the same essence. 

In some traditions, people may take some of the essence with them by touching one of their own belongings to a relic. The item itself does not become a relic but is considered to be endowed with the same essence. Think of it like using one candle to light others-- the flame passes on but does not diminish. 

Relics can serve as a focal point for prayer or as inspiration for Christians to also try to become so in tune with God that their bodies become holy, even after death. Beyond that, relics draw thousands of religious tourists to sites like the Notre Dame and the Scala Sancta every year!