Ibn 'Abbas (Allah be pleased with them) reported:I heard Allah's Messenger (ﷺ) 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

A hadith like this has been narrated by 'Amr on the authority of the same chain of transmitters

Ibn Juraij narrated this hadith with the same chain of transmitters, but he made no mention of it:" No person (man) should be alone with a woman except when there is a Mahram with her