وَمَا كَانَ لَهُ عَلَيْهِم مِّن سُلْطَانٍ إِلَّا لِنَعْلَمَ مَن يُؤْمِنُ بِالْآخِرَةِ مِمَّنْ هُوَ مِنْهَا فِي شَكٍّ وَرَبُّكَ عَلَى كُلِّ شَيْءٍ حَفِيظٌ

21 . And he had no warrant whatsoever against them , save that We would know him who believeth in the Hereafter from him who is in doubt thereof ; and thy Lord ( O Muhammad ) taketh note of all things .