Yahya related to me from Malik from Ibn Shihab that Ubaydullah
ibn Abdullah ibn Utba said, "I visited Umar ibn al-Khattab just before
noon and found him praying a voluntary prayer. So I stood behind him,
but he pulled me nearer and put me next to him, on his right hand
side, and then Yarfa came and I moved back and we formed a row behind
him."
Muwatta Malik Book 9, Hadith 37