Al-Kāfi - Volume 6 > The Undesirable Case of One’s Sleeping Alone and the Characteristics Prohibited because of its Frightfulness
Hadith #7

عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ الْأَشْعَرِيِّ عَنِ ابْنِ الْقَدَّاحِ عَنْ أَبِيهِ مَيْمُونٍ عَنْ أَبِي جَعْفَرٍ ( عليه السلام ) أَنَّهُ قَالَ لِمُحَمَّدِ بْنِ سُلَيْمَانَ أَيْنَ نَزَلْتَ قَالَ فِي مَكَانِ كَذَا وَ كَذَا قَالَ مَعَكَ أَحَدٌ قَالَ لَا قَالَ لَا تَكُنْ وَحْدَكَ تَحَوَّلْ عَنْهُ يَا مَيْمُونُ فَإِنَّ الشَّيْطَانَ أَجْرَأَ مَا يَكُونُ عَلَى الْإِنْسَانِ إِذَا كَانَ وَحْدَهُ .

7. A number of our people have narrated from Sahl ibn Ziyad from Ja‘far ibn Muhammad al-Ash‘ariy from ibn al-Qaddah from his father Maymun who has said the following: “Abu Ja‘far, ‘Alayhi al-Salam, once asked Muhammad ibn Sulayman, ‘Where have you found lodging?’ He replied, ‘It is in so and so place.’ He (the Imam) asked, ‘Is there anyone else with you?’ he replied, ‘No, there is no one with me.’ He (the Imam) said, ‘Move from there, O Maymun and do not stay there alone; Satan is most daring against man when he is alone.’”