"Do they not know that Allah extends the provision for whom He wills, and restricts it?"—that is, indeed, they have known.
Tafsir of Surah Az-Zumar from verse 53 to verse 56.
﴿أَوَ لَمْ يَعْلَمُوا أَنَّ اللَّهَ يَبْسُطُ الرِّزْقَ لِمَن يَشَاء وَيَقْدِرُ﴾ أَي: بلَى قد علمُوا.
تَفْسِير سُورَة الزمر من الْآيَة ٥٣ إِلَى آيَة ٥٦.