κοινωνητέον
From LSJ
ἀσκεῖν περὶ τὰ νοσήματα δύο, ὠφελεῖν ἢ μὴ βλάπτειν → strive, with regard to diseases, for two things — to do good, or to do no harm | as to diseases, make a habit of two things — to help, or at least, to do no harm
English (LSJ)
A one must share in, τινός τινι Pl.R.403b; φιλίας Ph.2.401; ὀνειδῶν Plu.Pomp.44.
Greek (Liddell-Scott)
κοινωνητέον: ῥημ. ἐπίθ., δεῖ κοινωνεῖν, τινός τινι Πλάτ. Πολ. 403Β.