Clement of Alexandria Exhortation to the Heathen Wherefore the blessed apostle says: "I testify in the Lord, that ye walk no longer as the Gentiles walk, in the vanity of their mind; having their understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the hardness of their heart: who, being past feeling, have given themselves over to lasciviousness, to work all uncleanness and concupiscence."[105] Tertullian On Modesty Branding, in fine, such as had denied themselves-Christians, to wit-on the score of having "delivered themselves up to the working of every impunity,"[204]