Yahya related to me from Malik from Ibn Shihab from Abdullah ibnAmir ibn Rabia that Umar ibn al-Khattab went out to ash-Sham. When hecame to Sargh, near Tabuk, he heard that the plague had broken out inash-Sham. Abd ar-Rahman ibn Awf told him that the Messenger of Allah,may Allah bless him and grant him peace, said, "If you hear that aland has a plague in it, do not go forward to it. If it comes upon aland which you are in, do not depart in flight from it." Umar ibn al-Khattab came back from Sargh.
USC-MSA web (English) reference: Book 45, Hadith 24
Arabic reference: Book 45, Hadith 1623