Tertullian,
Ante-Nicene Fathers Vol. III, Apologetic…
(1885)
“ For our religion commands us to love even our enemies, and to pray for those who persecute us, aiming at a perfection all its own, and seeking in its disciples something of a higher type than the commonplace goodness of the world. For all love those who love them; it is peculiar to Christians alone to love those that hate them. ”
