´It was narrated that Abu Al-Hawra' As-Sa'di said:` "I said to Al-Hasan bin 'Ali, may Allah be pleased with him: 'What did you memorize from the Messenger of Allah [SAW]?' He said: I memorized from him: 'Leave that which makes you doubt for that which does not make you doubt.'"
Hadith Referenceسنن نسائي / كتاب الأشربة / 5714
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح
´Al-Hasan bin 'Ali said:` "I remember that the Messenger of Allah (s.a.w) said: 'Leave what makes you in doubt for what does not make you in doubt. The truth brings tranquility while falsehood sows doubt.'" Another chain reports a similar narration.
Shaykh Dr. Abdur Rahman Freywai
Explanation: 1: The meaning is that one should avoid matters that are doubtful and uncertain, and act upon that which brings inner contentment, adopt truthfulness as your principle because it brings inner peace and tranquility, whereas falsehood leaves the heart restless and disturbed.
Source: Sunan al-Tirmidhi – Majlis ‘Ilmi Dar al-Da‘wah, New Delhi Edition, Page: 2518