moral imperative

noun2

1. •
   A practice, policy, or state of affairs which is required and justified by the fact that it is morally right.

   • This 60-second commercial, titled The Deficit Trials: 2017 A.D., . . . "expresses a view that budget cuts are a moral imperative." — 2001
2. •
   An ethical principle or rule which requires and justifies a practice, policy, or state of affairs.

   • . . . the Confucian custom of filial piety. This moral imperative requires sons to obey their parents and take care of them during old age. — 1996