﴿ فَضْلًۭا مِّنَ ٱللَّهِ وَنِعْمَةًۭ ۚ وَٱللَّهُ عَلِيمٌ حَكِيمٌۭ ﴾

“through God’s bounty and favour; and God is all-knowing, truly wise.”

that is a favour from God fadlan is a verbal noun in the accusative because of the implied verbal action that is afdala ‘He gives a favour’ and a grace from Him and God is Knower of them Wise in His bestowal of graces on them.