Sahih (Sahih Muslim)
وَحَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا هِشَامٌ، - يَعْنِي ابْنَ سُلَيْمَانَ - الْمَخْزُومِيُّ عَنِ ابْنِ، جُرَيْجٍ بِهَذَا الإِسْنَادِ نَحْوَهُ وَلَمْ يَذْكُرْ " لاَ يَخْلُوَنَّ رَجُلٌ بِامْرَأَةٍ إِلاَّ وَمَعَهَا ذُو مَحْرَمٍ " .
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