Abu Tu'mah says that once I was sitting with Sayyiduna Ibn Umar (may Allah be pleased with them) when a man came and said, "O Abu Abdur Rahman! I am able to fast while traveling." Sayyiduna Ibn Umar (may Allah be pleased with them) replied, "I heard the Prophet (peace and blessings of Allah be upon him) say that whoever does not accept the concession given by Allah, upon him is sin equal to the mountains of Arafah."