صحیح مسلم · Hadith 3273

Ibn 'Abbas (Allah be pleased with them) reported: I heard Allah's Messenger ( ‌صلی ‌اللہ ‌علیہ ‌وسلم ‌ ) delivering a sermon and making this observation: No person should be alone with a woman except when there is a Mahram with her, and the woman should not undertake journey except with a Mahram. A person stood up and said: Allah's Messenger, my wife has set out for pilgrimage, whereas I am enlisted to fight in such and such battle, whereupon he said: You go and perform Hajj with your wife.