Mukhtasar Muslim

It is narrated from Sayyiduna Hamzah bin Amr Aslami (may Allah be pleased with him) that I asked, "O Messenger of Allah! I find myself strong enough to fast while traveling, so if I fast (during travel), is there any sin upon me?" The Prophet (peace and blessings of Allah be upon him) said, "It is a concession from Allah. So whoever takes it has done well, and whoever wishes to fast, there is no sin upon him."