Sirach 22:26
Ben Sira, Ecclesiasticus26 But if harm should come to me because of him, whoever hears of it will beware of him. 27 Who will set a guard over my mouth, and an effective seal upon my lips, so that I may not fall because of them, and my tongue may not destroy me?
Ambrose On the Duty of the Clergy 3.22
129 If necessary, let us endure for a friend even hardship. Often enmity has to be borne for the sake of a friend's innocence; oftentimes revilings, if one defends and answers for a friend who is found fault with and accused. Do not be afraid of such displeasure, for the voice of the just says: Though evil come upon me, I will endure it for a friend's sake. In adversity, too, a friend is proved, for in prosperity all seem to be friends. But as in adversity patience and endurance are needed, so in prosperity strong influence is wanted to check and confute the arrogance of a friend who becomes overbearing.
Notes and References
"... The Book of Ecclesiasticus [Sirach] has been honored still more highly among the Christians, being cited in the Epistle of James (Edersheim, in Wace, 'Apocrypha,' p. 21), the Didache (4:5), and the Epistle of Barnabas (19:9), while Clement of Alexandria and Origen quote from it repeatedly, as from a γραφή, or holy book. In the Western Church, Cyprian frequently appeals to it in his 'Testimonia,' as does Ambrose in the greater number of his writings. In like manner the Catalogue of Cheltenham, Damasus I., the Councils of Hippo (393) and Carthage (397), Pope Innocent I., the second Council of Carthage (419), and Augustine all regard it as a canonical book. This is contrary, however, to the opinions of the Council of Laodicea, of Jerome, and of Rufinus of Aquileia, which authorities rank it among the ecclesiastical books. It was finally declared canonical by the Council of Trent; and the favor with which the Church has always regarded it has preserved it in its entirety. ..."
Toy, Crawford Howell The Wisdom of Jesus the Son of Sirach (pp. 1-10) Jewish Encyclopedia, 2021