Transgressing the Limits of Allah When Alone

Be not those who curse Iblis in public, but obey him in private.

Thawban reported that Rasulallah sallallahu ‘alaihi wasallam said:
“I certainly know people from my nation
who will come on the Day of Resurrection with good deeds like the mountains,
but Allah will scatter them like dust.”

Thawban said:
“O Messenger of Allah,
describe them to us and tell us more, so that we will not become like them.”

The Prophet said:
“They are your brothers and from your race, taking up worship at night as you do,
but they will be people who will transgress the sacred limits of Allah
while they are alone.

Sunan Ibn Majah