The following is a quote by Augustine, from the book Christian Faith and Criminal Justice, by Gerald Austin McHugh, Paulist press, 1978.

“St. Augustine…was known to frequently intervene in civil matters in an attempt to inject Christian values into legal and political matters. In one case, involving the murder of friends of his, Augustine wrote a letter to the judge which is one of the most remarkable witnesses to the Christian principle of “love of enemies” ever recorded. Fearing a death sentence, Augustine pleaded:

…by no means do this or permit this to be done. For although we might silently pass over the execution of criminals brought up for trial not by an accusation of ours…we do not wish the sufferings of the servants of God avenged by the infliction of precisely similar injuries in way of retaliation…Fulfill, Christian judge, the duty of an affectionate father; let your indignation against their crimes be tempered by considerations of humanity; be not provoked by the atrocity of their sinful deeds to gratify the passion of revenge, but rather be moved by the wounds which these deeds have inflicted on their own souls to exercise a desire to heal them…The Confessions and Letters of St. Augustine, Vol.I, Letter CXXXIII.” (my emphasis by bold sentence)