وَلَقَدْ مَكَّنَّٰهُمْ فِيمَآ إِن مَّكَّنَّٰكُمْ فِيهِ وَجَعَلْنَا لَهُمْ سَمْعًا وَأَبْصَٰرًا وَأَفْـِٔدَةً فَمَآ أَغْنَىٰ عَنْهُمْ سَمْعُهُمْ وَلَآ أَبْصَٰرُهُمْ وَلَآ أَفْـِٔدَتُهُم مِّن شَىْءٍ
"We had given them means We have not given you. We gave them hearing, eyes and hearts. But neither their hearing nor their eyes nor their hearts availed them anything."
The structure of the verse is built upon a repetition: the same three words are counted first in the sentence of giving, then in the sentence of being of no use.
The order itself carries information: it runs from the outside inwards — what is heard, what is seen, and at last what is weighed within.
أَفْـِٔدَة — root ف-ء-د: the core the lexicographers record is the burning of an ember; fuʾād is used for the kindled, moving side of the heart. How this root differs from qalb was treated in al-Wāqiʿa and in al-Najm; I do not repeat it here.
I record this as my own reading, and its support is the verse's own repetition: the instruments were given complete. The verse does not speak of an impossibility; it speaks of a means left unused. In the twenty-fourth verse they had seen the cloud — the eye was working.
إِذْ كَانُوا۟ يَجْحَدُونَ بِـَٔايَٰتِ ٱللَّهِ — and the cause is stated: جحود — root ج-ح-د: to deny a thing knowingly. The lexicographers also record the root's sense of "the ground being barren and dry" (arḍun jaḥād). That is, denial is described not as ignorance but as a ground that does not give back what it is given.