 The second commandment prohibits the use of God 's name in vain . Many ancient cultures believed that names were sacred ; some had prohibitions on when a person 's name could be spoken . The Gospel of John relates an incident where a group of Jews attempted to stone Jesus after he used a sacred name of God to refer to himself . They interpreted his statement as a claim of divinity . Since they did not believe that he was God , they considered this blasphemy , which under <unk> law carries a death penalty . Kreeft writes that all of the names by which God is known are holy , and thus all of those names are protected by the second commandment . The Catechism states , " Respect for his name is an expression of the respect owed to the mystery of God himself and to the whole sacred reality it evokes . " The Catechism also requires respect for the names of people out of respect for the dignity of that person . 
