Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that the Prophet Muhammad (peace and blessings be upon him) said: No man should sit in seclusion with a (non-mahram) woman, and no woman should travel unless she is accompanied by a mahram. At that moment, a companion stood up and said, "O Messenger of Allah, I have registered my name for such-and-such jihad, while my wife is going for Hajj." The Prophet said, "Then you should go and perform Hajj with your wife."