Alakendu Das was able to find the specific reference for the statement that I had asked about, and has kindly provided me with it. It is not the Bodhisattva-bhūmi directly, for which we already have the references thanks to Matthew and Dan, but rather is the 1932 book by Har Dayal, The Bodhisattva Doctrine in Buddhist Sanskrit Literature, pp. 207-208. In Chapter 5, "The Pāramitās," in the section on śīla-pāramitā, Har Dayal discusses the ten constituents of śīla and then writes about the motives and sanctions for such right action, concluding (p. 205): "Pure hedonism thus seems to be the ruling theory of Buddhist ethics."
A few pages later we come to the doctrine in question (p. 207): "The Mah
āy
ānists have thus gone through the entire gamut of the motives that govern human conduct. But they have rather stultified themselves by teaching the strange doctrine that a bodhisattva may violate any or all of the precepts of
śīla, if he is moved by compassion for others. This view has led to much subtle casuistry. The Bo. Bh
ū. [Bodhisattva-bh
ūmi] and other treatises explain that the ethical rules are not absolute. They may be infringed, if a bodhisattva can thereby render service to an unfortunate creature. . . . The medieval monks of Europe also passed through a period of widespread corruption; but they did not formulate a regular philosophy of degeneracy. The later Mah
āy
ānists sought to justify the sensual escapades of the monks (alias bodhisattvas) by referring to the assumed motive of karu
ṇā. Tantrism cast its shadow before." (p. 208): "The author of the Bodhisattva-bh
ūmi indicates the circumstances, in which a bodhisattva may infringe the seven chief precepts. He may kill a person, who intends to murder a monk or his own parents. . . . In this way, the Mah
āy
ānists teach that the end justifies the means and that a bodhisattva may sometimes adopt St. Paul's device of 'becoming all things to all men'."
I had never read this book by Har Dayal, and I can only say that I understand the Bodhisattva-bhūmi differently than he does. Nor do I think that Har Dayal's understanding is supported by the good examples from history provided by Dan and Matthew, of the killing of the "evil king" Glang-dar-ma, or more recently the justification by the Tibetan president of the Chinese Buddhist Association of some of the excesses of Maoist policy. Of course, we today have a major advantage over Har Dayal in that we have direct access to the Tibetan tradition of exegesis, so that we can see how this book was there understood, and to Tibetan culture and history, so that we can see how these ethics played out in real life.
Best regards,
David Reigle
Colorado, U.S.A.