 For the first two hundred years , Christians " refused to kill in the military , in self @-@ defense , or in the judicial system " , but there was no official Church position on the death penalty . When the Church was first officially recognized as a public institution in 313 , its attitude toward capital punishment became one of toleration but not outright acceptance . The death penalty had support from early Catholic theologians , though some of them such as Saint Ambrose encouraged members of the clergy not to pronounce or carry out capital punishment . Saint Augustine answered objections to capital punishment rooted in the first commandment in The City of God . Thomas Aquinas and Duns Scotus argued that civil authority to carry out capital punishment was supported by scripture . Pope Innocent III required Peter Waldo and the Waldensians to accept that " secular power can , without mortal sin , exercise judgement of blood , provided that it punishes with justice , not out of hatred , with prudence , not precipitation " as a prerequisite for reconciliation with the church . Paul Suris states that official Church teachings have neither absolutely condemned nor promoted capital punishment , but toleration of it has fluctuated throughout the ages . The Inquisitions provide the most memorable instance of Church support for capital punishment , although some historians considered these more lenient than the secular courts of the period . 
