Yahya related to me from Malik from Hisham ibn Urwa from his father that Hamza ibn Amr al-Aslami once said to the Messenger of Allah, may Allah bless him and grant him peace, "Messenger of Allah, I am a man who fasts. Can I fast when travelling?" The Messenger of Allah, may Allah bless him and grant him peace, said, "If you want you can fast, and if you want you can break the fast."