Riyad as-Salihin, Book 18, Hadith 1629 (In-Book) ⓘ
Ibn Abbas (May Allah be pleased with them) said: The Messenger of Allah said, "No one of you should meet a woman in privacy unless she is accompanied by a Mahram (i.e., a relative within the prohibited degrees)."[Al-Bukhari and Muslim].
وعن ابن عباس رضي الله عنهما أن رسول الله صلى الله عليه وسلم قال: "لا يخلون أحدكم بامرأة إلا مع ذي محرم" ((متفق عليه)).