Or have they the treasures of the mercy of your Lord, the Almighty, the Real Bestower?
meaning, the Almighty Whose might cannot be overcome, the Bestower Who gives whatever He wills to whomsoever He wills.
This Ayah is like the Ayah;
أَمْ لَهُمْ نَصِيبٌ مِّنَ الْمُلْكِ فَإِذاً لاَّ يُوْتُونَ النَّاسَ نَقِيراً
أَمْ يَحْسُدُونَ النَّاسَ عَلَى مَأ ءَاتَـهُمُ اللَّهُ مِن فَضْلِهِ فَقَدْ ءَاتَيْنَأ ءَالَ إِبْرَهِيمَ الْكِتَـبَ وَالْحِكْمَةَ وَءَاتَيْنَـهُمْ مُّلْكاً عَظِيماً
فَمِنْهُمْ مَّنْ ءَامَنَ بِهِ وَمِنْهُمْ مَّن صَدَّ عَنْهُ وَكَفَى بِجَهَنَّمَ سَعِيراً
Or have they a share in the dominion? Then in that case they would not give mankind even a speck on the back of a date stone. Or do they envy men for what Allah has given them of His bounty? Then, We had already given the family of Ibrahim the Book and Al-Hikmah, and conferred upon them a great kingdom. Of them were (some) who believed in him, and of them were (some) who averted their faces from him; and enough is Hell for burning (them). (4;53-55)
قُل لَّوْ أَنتُمْ تَمْلِكُونَ خَزَايِنَ رَحْمَةِ رَبِّى إِذًا لامْسَكْتُمْ خَشْيَةَ الاِنفَاقِ وَكَانَ الانْسَـنُ قَتُورًا
Say;"If you possessed the treasure of the mercy of my Lord (wealth), then you would surely hold back for fear of (being exhausted), and man is ever miserly!" (17;100)
This is after Allah tells us the story of how the disbeliever denied the sending of a human Messenger, as He tells us that the people of Salih, peace be upon him, said;
أَءُلْقِىَ الذِّكْرُ عَلَيْهِ مِن بَيْنِنَا بَلْ هُوَ كَذَّابٌ أَشِرٌ
سَيَعْلَمُونَ غَداً مَّنِ الْكَذَّابُ الاٌّشِرُ
"Is it that the Reminder is sent to him alone from among us? Nay, he is an insolent liar!"
Tomorrow they will come to know who is the liar, the insolent one! (54;25-26)
أَمْ لَهُم مُّلْكُ السَّمَاوَاتِ وَالاَْرْضِ وَمَا بَيْنَهُمَا فَلْيَرْتَقُوا فِي الاَْسْبَابِ