There isn’t any such concept. A burglar should also warn others from stealing.

Is there any such concept in Islam that a sinner, say a thief cannot sincerely warn others against a lesser sin like backbiting or music?

Sins | March 16, 2014 6:03 pm
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Please mention some of the major sins as I’m unable to find the lists on the internet.
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Is it permissible to worship when the sun is actually rising towards the sky and the same when it is actually coming down?