(37) باب تَوْقِيرِهِ صلى الله عليه وسلم وَتَرْكِ إِكْثَارِ سُؤَالِهِ عَمَّا لاَ ضَرُورَةَ إِلَيْهِ أَوْ لاَ يَت
This hadith has been transmitted on the authority of 'Amir b. Sa'd and the words are. Allah's Messenger (ﷺ) said:
The greatest sinner of the Muslims amongst Muslims is one who asked about a certain thing which had not been prohibited and it was prohibited because of his asking about it.
Reference: Sahih Muslim 2358 b
In-book reference: Book 43, Hadith 175
USC-MSA web (English) reference(deprecated numbering scheme): Book 30, Hadith 5822