ʿAli ؓ said: I used to enter upon the Messenger of Allah ﷺ twice, by night and by day. If I entered upon him and he was praying, he would clear his throat. I came to him one night and he said: ʿDo you know what the angel did this night? I was praying and I heard some movement in the house. I went out and I saw Jibreel (عليه السلام). He said: All night I have been waiting for you. In your house there is a dog and I could not enter. We do not enter the house in which there is a dog or a person who is junub or a statue.ʿ  

عَلِيٌّ كَانَ لِي مِنْ رَسُولِ اللهِ ﷺ مَدْخَلانِ بِاللَّيْلِ وَالنَّهَارِ وَكُنْتُ إِذَا دَخَلْتُ عَلَيْهِ وَهُوَ يُصَلِّي تَنَحْنَحَ فَأَتَيْتُهُ ذَاتَ لَيْلَةٍ فَقَالَ أَتَدْرِي مَا أَحْدَثَ الْمَلَكُ اللَّيْلَةَ؟ كُنْتُ أُصَلِّي فَسَمِعْتُ خَشْفَةً فِي الدَّارِ فَخَرَجْتُ فَإِذَا جِبْرِيلُ عَلَيْهِ السَّلامُ فَقَالَ مَا زِلْتُ هَذِهِ اللَّيْلَةَ أَنْتَظِرُكَ إِنَّ فِي بَيْتِكَ كَلْبًا فَلَمْ أَسْتَطِعِ الدُّخُولَ وَإِنَّا لَا نَدْخُلُ بَيْتًا فِيهِ كَلْبٌ وَلا جُنُبٌ وَلا تِمْثَالٌ