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Surah 13. Ar-Ra'd
Ayah 27 - 29
٢٧. وَيَقُولُ ٱلَّذِينَ كَفَرُوا۟ لَوْلَآ أُنزِلَ عَلَيْهِ ءَايَةٌ مِّن رَّبِّهِۦ ۗ قُلْ إِنَّ ٱللَّهَ يُضِلُّ مَن يَشَآءُ وَيَهْدِىٓ إِلَيْهِ مَنْ أَنَابَ
٢٨. ٱلَّذِينَ ءَامَنُوا۟ وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ ٱللَّهِ ۗ أَلَا بِذِكْرِ ٱللَّهِ تَطْمَئِنُّ ٱلْقُلُوبُ
٢٩. ٱلَّذِينَ ءَامَنُوا۟ وَعَمِلُوا۟ ٱلصَّـٰلِحَـٰتِ طُوبَىٰ لَهُمْ وَحُسْنُ مَـَٔابٍ
[27-29] Those people who have rejected (Muhammad as a Prophet) say, "Why has no Sign been sent down to him from his Lord?43 Say, "Allah leads astray whom He will; and He leads to Himself only those who turn to Him."44 Such are the people who have accepted (the Message of this Prophet,) and their hearts find comfort in the remembrance of Allah. Note it well that it is Allah's remembrance alone that brings comfort to hearts. Blessed are those who have accepted the Message and done righteous deeds: they have a good end.
43Please also keep in view the answer that has been given to this question in v.7.
44This is the answer to their question. It is not due to the lack of signs that they were going astray, but it is the lack of any desire in them to seek right guidance. For Allah does not force one to follow the Right Way, if he deliberately turns away from it. He lets such persons wander on the wrong ways they choose to wander. Nay, even all those things that should serve as a means to guidance for a seeker of truth, become the means of deviation for the one who seeks deviation. So much so that that very torch which helps show the way to the former, dazzles the eyes of the latter. This is how Allah Leads astray a person.
This answer to the demand of a Sign is matchless in its eloquence. It says to them, "O foolish people! it is not due to the lack of Signs that you are not finding the right path, but it is due to the lack of any desire in you for it. You do not see any of the countless Signs that lie scattered all around you because you have no desire to go to the Right Way. How can then any Sign be helpful to you ? For you would not see any of those Signs. However, those who seek the Right Way to Allah, see these Signs and find the Right Way with their help."