Hadith 29:134
Abu Usama narrated to us, from Abu Awn, from Muhammad, who said: It was mentioned to him that Umar returned from al-Sham when he heard that the plague was there. He did not recognize him, and he said: "He was only informed that the summer expedition would not go out this year, so he returned."
حدثنا أبو أسامة عن أبي عون عن محمد قال ذكر له أن عمر رجع من الشام حين سمع أن الوباء بها فلم يعرفه وقال إنما أخبر أن المصايفة لا تخرج العام فرجع