score:2
Okay I found the answer.
It's from the "SΕ«tra of the UpΔsaka Precepts" (Shansheng Jing). It was translated into Chinese in the 5th century.
http://www.sutrasmantras.info/sutra33c.html
This sutra has similarities to the older Sigalovada Sutta http://www.accesstoinsight.org/tipitaka/dn/dn.31.0.ksw0.html
(Ref comparing the UPS and Sigalovada: "Buddhism and Peace", chapter 10)