Muwatta Malik 396
موطأ مالك#396SahihYahya related to me from Malik that he had heard that Abdullah ibn Masud used to move forward while in ruku
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 9:71