From the route of Abu Muhammad al-Hasan bin ^Aliyy bin Abi Talib, the Beloved One and grandson of the Prophet, sallallahu ^alayhi wa sallam from his daughter, who said: I have memorized from the Messenger of Allah, sallallahu ^alayhi wa sallam,
<<Do not do the matter (whether lawful or legitimate) in which you have doubt about its judgment, and resort to doing the matter that you do not have doubt about its judgment.>>
Narrated by at-Tirmidhiyy and an-Nasa‘iyy, at-Tirmidhiyy said this Hadith is Hasan and Sahih.