Sirach 7:29
Ben Sira, Ecclesiasticus27 With all your heart honor your father, and do not forget the birth pangs of your mother. 28 Remember that it was of your parents you were born; how can you repay what they have given to you? 29 With all your soul fear the Lord, and revere his priests. 30 With all your might love your Maker, and do not neglect his ministers. 31 Fear the Lord and honor the priest, and give him his portion, as you have been commanded: the first fruits, the guilt offering, the gift of the shoulders, the sacrifice of sanctification, and the first fruits of the holy things.
Didache 4:1
1 My child, thou shalt remember, day and night, him who speaks the word of God to thee, and thou shalt honor him as the Lord, for where the Lord's nature is spoken of, there is he present. 2 And thou shalt seek daily the presence of the saints, that thou mayest find rest in their words. 3 Thou shalt not desire a schism, but shalt reconcile those that strive. Thou shalt give righteous judgement; thou shalt favor no mans person in reproving transgression.
Notes and References
Jefford, Clayton N. "The Wisdom of Sirach and the Glue of the Matthew–Didache Tradition" in Bingham, D. Jeffrey, editor. Intertextuality in the Second Century (pp. 8-23) Brill, 2016