David Steinberg was ubiquitous on television in the '70s - appearing as frequent guest and fill-in host on the Tonight Show, and performing stand-up routines on any show that would have him.
Am told (by IMDB.com, no less) that his "religious" monologues are one of the reasons CBS canceled The Smothers Brothers. I find this hard to believe, because Steinberg never seemed the least bit controversial back then. His biggest "bit" was screaming "Bugga-Bugga!" during a psychiatrist sketch.
Steinberg dropped off the face of the Earth at some point during the '80s. I always assumed he was working in his native Canada (where he hosted a terrible variety show in 1976 with the cast of SCTV as his co-stars).
David Steinberg - the comedian - may be forgotten, but he's far from gone; he's one of the directors on Curb Your Enthusiasm, and has worked as a director steadily for over 25 years.
This clip has a small audio glitch in the middle, but it set-up and punchline are intact.