Bhagavatapurana 7.15.66

7.15.66

yadyasya vāniṣiddhaṃ syādyena yatra yato nṛpa /
sa teneheta kāryāṇi naro nānyairanāpadi //

66. Whatever is not prohibited for any one and what must be done in some particular manner, at a particular place or time, he should proceed to do in the same way, but not differently except under insuperable danger and difficulty.