Definition of "incumbent on" []

• Morally binding or necessary (adjective)

WordNet. Princeton University. 2010.

• ""Wine?" asked Walsingham, in a manner that made it incumbent on Phelippes to refuse."
• "But of the laws of this period we have a tolerable collection by Lambard and Wilkins, probably not perfect, but neither very defective; and if any one chooses to build a doctrine on any law of that period, supposed to have been lost, it is incumbent on him to prove it to have existed, and what were its contents."
• "On a Class IVb world, he knew, it was as incumbent on him to stay out of view and not reveal himself to the locals as it was for the Teacher."