While I was going with the Prophet ﷺ through the ruins of Medina and he was reclining on a date-palm leaf stalk, some Jews passed by. Some of them said to the others: Ask him (the Prophet) about the spirit. Some of them said that they should not ask him that question as he might give a reply which would displease them. But some of them insisted on asking, and so one of them stood up and asked, "O Abul-Qasim ! What is the spirit?" The Prophet ﷺ remained quiet. I thought he was being inspired Divinely. So I stayed till that state of the Prophet (while being inspired) was over. The Prophet ﷺ then said, "And they ask you (O Muhammad) concerning the spirit --Say: The spirit -- its knowledge is with my Lord. And of knowledge you (mankind) have been given only a little)." (17.85)  

بَيْنَا أَنَا أَمْشِي مَعَ النَّبِيِّ ﷺ فِي خَرِبِ الْمَدِينَةِ وَهُوَ يَتَوَكَّأُ عَلَى عَسِيبٍ مَعَهُ فَمَرَّ بِنَفَرٍ مِنَ الْيَهُودِ فَقَالَ بَعْضُهُمْ لِبَعْضٍ سَلُوهُ عَنِ الرُّوحِ وَقَالَ بَعْضُهُمْ لاَ تَسْأَلُوهُ لاَ يَجِيءُ فِيهِ بِشَىْءٍ تَكْرَهُونَهُ فَقَالَ بَعْضُهُمْ لَنَسْأَلَنَّهُ فَقَامَ رَجُلٌ مِنْهُمْ فَقَالَ يَا أَبَا الْقَاسِمِ مَا الرُّوحُ فَسَكَتَ فَقُلْتُ إِنَّهُ يُوحَى إِلَيْهِ فَقُمْتُ فَلَمَّا انْجَلَى عَنْهُ قَالَ {وَيَسْأَلُونَكَ عَنِ الرُّوحِ قُلِ الرُّوحُ مِنْ أَمْرِ رَبِّي وَمَا أُوتُيتُمْ مِنَ الْعِلْمِ إِلاَّ قَلِيلاً} قَالَ الأَعْمَشُ هَكَذَا فِي قِرَاءَتِنَا  

I was a blacksmith in the Pre-Islamic period, and 'Asi bin Wail owed me some money, so I went to him to demand it. He said (to me), "I will not pay you unless you disbelieve Muhammad." I said, "I will not disbelieve till Allah kills you and then you get resurrected." He said, "Leave me till I die and get resurrected, then I will be given wealth and children and I will pay you your debt." On that occasion it was revealed to the Prophet: 'Have you seen him who disbelieved in Our signs and says: Surely I will be given wealth and children? Has he known the unseen, or has he taken a covenant from the Beneficent (Allah)? (19.77- 78)  

لاَ أُعْطِيكَ حَتَّى تَكْفُرَ بِمُحَمَّدٍ ﷺ فَقُلْتُ لاَ أَكْفُرُ حَتَّى يُمِيتَكَ اللَّهُ ثُمَّ تُبْعَثَ قَالَ دَعْنِي حَتَّى أَمُوتَ وَأُبْعَثَ فَسَأُوتَى مَالاً وَوَلَدًا فَأَقْضِيَكَ فَنَزَلَتْ {أَفَرَأَيْتَ الَّذِي كَفَرَ بِآيَاتِنَا وَقَالَ لأُوتَيَنَّ مَالاً وَوَلَدًا * أَطَّلَعَ الْغَيْبَ أَمِ اتَّخَذَ عِنْدَ الرَّحْمَنِ عَهْدًا }