"Have you not seen those who claim purity for themselves?" The interpretation of Qatadah: They are the Jews who claimed purity for themselves in a matter they had not attained. They said: "We are the sons of Allah and His beloved ones." "But Allah purifies whom He wills, and they will not be wronged, even as much as a fatil." The fatil: what is in the belly of the date-stone, from its membrane.
﴿أَلَمْ تَرَ إِلَى الَّذِينَ يُزَكُّونَ أنفسهم﴾ تَفْسِير قَتَادَة: هم الْيَهُود زكوا أنفسهم بِأَمْر لم يبلغوه؛ قَالُوا: نَحْنُ أَبنَاء الله وأحباؤه ﴿بَلِ اللَّهُ يُزَكِّي مَنْ يَشَاءُ وَلا يظْلمُونَ ينقصُونَ (فتيلاً﴾ الفتيل: مَا كَانَ فِي بطن النواة من لحائها.
