الأربعون النووية
Forty Hadith of an-Nawawi
Hadith 11, 40 Hadith an-Nawawi

On the authority of Abu Muhammad al-Hasan ibn Ali ibn Abee Talib (may Allah be pleased with him), the grandson of the Messenger of Allah (peace and blessings of Allah be upon him), and the one much loved by him, who said:

I memorised from the Messenger of Allah (peace and blessings of Allah be upon him): “Leave that which makes you doubt for that which does not make you doubt.”

[At-Tirmidhi] [An-Nasai]

At-Tirmidhi said that it was a good and sound (hasan saheeh) hadeeth.

عَنْ أَبِي مُحَمَّدٍ الْحَسَنِ بْنِ عَلِيِّ بْنِ أَبِي طَالِبٍ سِبْطِ رَسُولِ اللَّهِ صلى الله عليه و سلم وَرَيْحَانَتِهِ رَضِيَ اللَّهُ عَنْهُمَا، قَالَ: حَفِظْت مِنْ رَسُولِ اللَّهِ صلى الله عليه و سلم "دَعْ مَا يُرِيبُك إلَى مَا لَا يُرِيبُك".
رَوَاهُ التِّرْمِذِيُّ [رقم:2520]،
[وَالنَّسَائِيّ]
وَقَالَ التِّرْمِذِيُّ: حَدِيثٌ حَسَنٌ صَحِيحٌ.
Reference : Hadith 11, 40 Hadith an-Nawawi