Abu Tufail ‘Amir b. Withila (RA) reported: I was in the company of ‘Ali b. Abi Talib, when a person came to him, and said: What was it that Allah’s Apostle (peace be upon him) told you in secret? Thereupon he (liadrat ‘All) was enraged and said: Allah’s Apostle (peace be upon him) did not tell me anything in secret that he hid from people, except that he told me four things. He said: Com- mader of Faithful, what are these? He said: Allah cursed him who cursed his father; Allah cursed him who sacrificed for anyone besides Allah; and Allah cursed him who accommodates an innovator (in religion); and Allah cursed him who changed the minarets (the boundary lines) of the land.
Sahih Muslim, Book 35, Hadith 60