It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "No woman should travel without a mahram." A man came to the Prophet (peace and blessings be upon him) and said, "My wife is going for Hajj while my name has been registered for such-and-such army for jihad." The Prophet (peace and blessings be upon him) said: "Go, and perform Hajj with your wife."