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."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5392
Hadith Gradingحکم دارالسلام:إسناده ضعيف ، لضعف ابن لهيعة .