What is the reason for the singular form of the word "their hearing" (سمعهم) in His saying, the Almighty: "Allah has set a seal upon their hearts and upon their hearing and upon their eyesight is a veil. And for them is a great torment," despite the plural forms of "their hearts" (قلوبهم) and "their eyesight" (أبصارهم)?

The reason for singling out the word "hearing" (السمع) in the noble verse is that "hearing" (السمع) is a verbal noun (masdar) that denotes both small and large quantities, unlike "sight" (البصر) which is not a verbal noun. It was also said that when "hearing" was attributed to the collective, it indicated the hearings of the collective, similar to the poet's saying "their skins" (جلودها), where he used a singular form (for "skin") while referring to a plural.