"Indeed, they are a people who keep themselves pure," meaning: they abstain from your deeds, and therefore they do not do what you do.
﴿إِنَّهُم أنَاس يتطهرون﴾ أَيْ: يَتَنَزَّهُونَ عَنْ أَعْمَالِكُمْ، فَلَا يعْملُونَ مَا تَعْمَلُونَ
