(37) باب تَوْقِيرِهِ صلى الله عليه وسلم وَتَرْكِ إِكْثَارِ سُؤَالِهِ عَمَّا لاَ ضَرُورَةَ إِلَيْهِ أَوْ لاَ يَت
Amir b. Sa'd reported on the authority of his father that Allah's Messenger (ﷺ) said:
The greatest sinner amongst the Muslims is one who asked about a thing (from Allah's Apostle) which had not been forbidden for the Muslims and it was forbidden for them because of his persistently asking about it.
Reference: Sahih Muslim 2358 a
In-book reference: Book 43, Hadith 174
USC-MSA web (English) reference(deprecated numbering scheme): Book 30, Hadith 5821