جَزَآءً وِفَاقًا
Sentence structure
An understood verb such as “they are recompensed” is emphasized by جَزَآءً, a cognate accusative. وِفَاقًا describes that recompense as exactly corresponding to their deeds.
جَزَآءًۭ — a recompense
Grammar: An indefinite accusative verbal noun functioning as a cognate accusative مفعول مطلق for an understood verb such as جُوزُوا.
وِفَاقًا — exactly fitting
Grammar: An indefinite accusative masculine verbal noun functioning as an adjective of جَزَآءً, meaning a recompense fully corresponding to the deeds.