I said to al-Ḥasan b. ʿAlī: What did you memorize from the Messenger of Allah ﷺ? He said: I memorized from him: "Leave what makes you doubt for what does not make you doubt. The truth brings tranquility while falsehood sows doubt."  

قُلْتُ لِلْحَسَنِ بْنِ عَلِيٍّ: مَا حَفِظْتَ مِنْ رَسُولِ اللَّهِ ﷺ؟ قَالَ: حَفِظْتُ مِنْ رَسُولِ اللَّهِ ﷺ: «دَعْ مَا يَرِيبُكَ إِلَى مَا لاَ يَرِيبُكَ، فَإِنَّ الصِّدْقَ طُمَأْنِينَةٌ وَإِنَّ الْكَذِبَ رِيبَةٌ۔»