Musannaf Ibn Abi Shaybah

Muhammad bin Ja'far bin Zubair narrated that the Messenger of Allah, peace and blessings be upon him, sent Abdullah bin Unais to Khalid bin Sufyan. The narrator said: So when I reached near him, and it was the time of Asr, I feared that he might be engaged or that some action might begin before I reached him, so I prayed while walking.