Musnad Ahmad 10:24

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, from 'Abd al-Hamid ibn 'Abd al-Rahman ibn Zayd ibn al-Khattab, from 'Abd Allah ibn 'Abd Allah ibn al-Harith ibn Nawfal, from 'Abd Allah ibn 'Abbas, who said: 'Umar ibn al-Khattab set out intending for al-Sham—and he mentioned the hadith—he said: 'Abd al-Rahman ibn 'Awf was absent, then he came and said: "I have knowledge regarding this. I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'If you hear of it in a land, do not advance toward it, and if it occurs in a land while you are in it, do not depart from it fleeing from it.'"