Muwatta Malik 341
موطأ مالك#341SahihYahya related to me from Malik from Nafi that he used to travel one mail-stage with Ibn Umar, and he would not shorten the prayer
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: 9:16