Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XIX

Chapter XIX.—Not Peace, But a Sword.

“Whence the Prophet of the truth, knowing that the world was much in error, and seeing it ranged on the side of evil, did not choose that there should be peace to it while it stood in error.  So that till the end he sets himself against all those who are in concord with wickedness, setting truth over against error, sending as it were fire upon those who are sober, namely wrath against the seducer, which is likened to a sword, 1132 and by holding forth the word he destroys ignorance by knowledge, cutting, as it were, and separating the living from the dead.  Therefore, while wickedness is being conquered by lawful knowledge, war has taken hold of all.  For the submissive son is, for the sake of salvation, separated from the unbelieving father, or the father from the son, or the mother from the daughter, or the daughter from the mother, and relatives from relatives, and friends from associates.

Footnotes

Matt. x. 34.