Lex orandi, lex credendi

Lex orandi, lex credendi (Latin: "the law of what is prayed [is] the law of what is believed"), sometimes expanded as Lex orandi, lex credendi, lex vivendi (Latin: "the law of what is prayed [is] what is believed [is] the law of what is lived"), is a motto in Christian tradition, which means that prayer and belief are integral to each other and that liturgy is not distinct from theology. It refers to the relationship between worship and belief. Its simplistic applicability as a self-standing principle independent of hope and charity was bluntly denied by Pope Pius XII, who positioned liturgy as providing theological evidence not authority.