It is narrated from Sayyiduna Hamzah bin Amr Al-Aslami (may Allah be pleased with him) that he asked the Prophet Muhammad (peace and blessings be upon him) about fasting while traveling, and he used to fast continuously. So the Prophet Muhammad (peace and blessings be upon him) said: "You have the choice; if you wish, then fast, and if you wish, then leave the fast."