أَتَأْذَنُ لِي أَنْ أَكُونَ مَعَكُما تَحْتَ الْكِساءِ فَقُلْتُ: نَعَمْ إِنَّ جَدَّكَ وَأَخاكَ تَحْتَ الْكِساءِ. Inside the verse of purity the word Bayt is singular, and is not wives of Ahle Bayt but Ahle Buyoot, which means of different homes, and Alif and Laam continues to be enjoined to Bayt, from https://nybookmark.com/story12892986/the-best-side-of-hadis-kisa