3 occurrences across the corpus

Apostolic Fathers

Ignatius to the Magnesians 2:6

Wherefore taking the same holy course, see that ye all reverence one another: and let no one look upon his neighbour after the flesh; but do ye all mutually love each other in Jesus Christ.

Jubilees

Jubilees 37:4

my father food and drink, and my father blessed him and put me under his hand. And now our father has caused us to swear, me and him, that we shall not mutually devise evil, either against his brother, and that we shall continue in love and in peace each with his brother and not make our ways

NT Apocrypha/Pseudepigrapha

The Passion of the Holy Martyrs Perpetua and Felicitas 4:1

Again, after a few days, Pudens, a soldier, an assistant overseer of the prison, who began to regard us in great esteem, perceiving that the great power of God was in us, admitted many brethren to see us, that both we and they might be mutually refreshed. And when the day of the exhibition drew near, my father, worn with suffering, came in to me, and began to tear out his beard, and to throw himself on the earth, and to cast himself down on his face, and to reproach his years, and to utter such words as might move all creation. I grieved for his unhappy old age.