It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) set out with the intention of going to Syria . . . . . . Sayyiduna Abdur Rahman bin Awf (may Allah be pleased with him) was not present at that time; when he arrived, he said, "I have accurate knowledge about this. I heard the Prophet (peace and blessings of Allah be upon him) say: 'If you hear of an epidemic in a land, do not go there, and if it breaks out in a land where you are, do not leave from there.'"