In which sutta does Buddha say roughly '..and that would bring me sorrow[sad]?

I recall regarding a sutta awhile back of an encounter between Buddha and some wandering ascetic (not Bahiya). in that, the ascetic might have been too old or whatever, and buddha discourages him and explains **his** grief if things didn't work out. note: i don't recall if it was an ascetic or old, just that it was an encounter with non-sangha person. any arhat saying something similar would suffice.