Musannaf Ibn Abi Shayba 36:527

Ibn Idris narrated to us, from Talha bin Yahya, from his two paternal uncles, Isa bin Talha and Urwah bin al-Zubayr, who both said: Umar said: "Let Suhayb lead you in prayer for three [days], and observe. If that is the case [i.e., if the matter is settled], then [it is well]; otherwise, the affair of Muhammad shall not be left for more than three [days] without a leader."