Muwatta Malik 1403
موطأ مالك#1403Da'ifMalik related to me that Umar ibn al-Khattab said, "The testimony of some one known to bear a grudge or to be unreliable is not accepted
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Daif
In-book reference: 36:5