Tafsir of Ar-Ra'd 13:19

{أَفَمَن يَعْلَمُ أَنَّمَا أُنزِلَ إِلَيْكَ مِن رَّبِّكَ الْحَقُّ كَمَنْ هُوَ أَعْمَىٰ}

The interrogative particle of denial (hamzat al-inkār) is prefixed to the fa in His saying: {أَفَمَن يَعْلَمُ} (Is then he who knows...). This is to deny that any ambiguity could remain after the parable has been struck, illustrating that the state of one who knows {أَنَّمَا أُنزِلَ إِلَيْكَ مِن رَّبِّكَ الْحَقُّ} (that what has been revealed to you from your Lord is the truth) and thus responds, is as far removed from the state of the ignorant one who has no insight and does not respond, as the distance between foam and water, or dross and pure gold.

{إِنَّمَا يَتَذَكَّرُ أُولُو الْأَلْبَابِ} Meaning: Those who act according to the dictates of their intellects, and thus have observed and gained insight.

{الَّذِينَ يُوفُونَ بِعَهْدِ اللَّهِ وَلَا يَنقُضُونَ الْمِيثَاقَ}

{وَالَّذِينَ يَصِلُونَ مَا أَمَرَ اللَّهُ بِهِ أَن يُوصَلَ وَيَخْشَوْنَ رَبَّهُمْ وَيَخَافُونَ سُوءَ الْحِسَابِ}

{وَالَّذِينَ صَبَرُوا ابْتِغَاءَ وَجْهِ رَبِّهِمْ وَأَقَامُوا الصَّلَاةَ وَأَنفَقُوا مِمَّا رَزَقْنَاهُمْ سِرًّا وَعَلَانِيَةً وَيَدْرَءُونَ بِالْحَسَنَةِ السَّيِّئَةَ أُولَٰئِكَ لَهُمْ عُقْبَى الدَّارِ}

{جَنَّاتُ عَدْنٍ يَدْخُلُونَهَا وَمَن صَلَحَ مِنْ آبَائِهِمْ وَأَزْوَاجِهِمْ وَذُرِّيَّاتِهِمْ ۖ وَالْمَلَائِكَةُ يَدْخُلُونَ عَلَيْهِم مِّن كُلِّ بَابٍ}

{سَلَامٌ عَلَيْكُم بِمَا صَبَرْتُمْ ۚ فَنِعْمَ عُقْبَى الدَّارِ}