Zayd ibn Aslam reported from his father that 'Umar used to say on the minbar, "O people! Improve your homes but be careful about these house snakes [which are a form of jinn] before they make you afraid. Those among them which are Muslim will not be clear to you and, by Allah, we have not made peace with them since the time when we treated them as an enemy."

حَدَّثَنَا عَبْدُ اللهِ بْنُ يُوسُفَ، قَالَ‏:‏ حَدَّثَنَا اللَّيْثُ، قَالَ‏:‏ حَدَّثَنَا ابْنُ عَجْلاَنَ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ قَالَ‏:‏ كَانَ عُمَرُ يَقُولُ عَلَى الْمِنْبَرِ‏:‏ يَا أَيُّهَا النَّاسُ، أَصْلِحُوا عَلَيْكُمْ مَثَاوِيكُمْ، وَأَخِيفُوا هَذِهِ الْجِنَّانَ قَبْلَ أَنْ تُخِيفَكُمْ، فَإِنَّهُ لَنْ يَبْدُوَ لَكُمْ مُسْلِمُوهَا، وَإِنَّا وَاللَّهِ مَا سَالَمْنَاهُنَّ مُنْذُ عَادَيْنَاهُنَّ‏.‏