Tafsir of Ad-Dukhan 44:57

(A bounty from your Lord) meaning: They were given all of that as a gift and a bounty from Him, the Exalted. It is in the accusative case (nasb) as a verbal noun (al-masdariyyah). It is also permissible for it to be a circumstantial qualifier (hal) or a causal object (maf'ul lahu). In any case, it contains an indication that their deeds do not necessitate recompense from Him, Glorified and Exalted is He. It was also recited as (fadlun) in the nominative case, meaning: "That is a bounty."

(That is the great attainment)

(Because it is the attainment of [all] desires and salvation from [all] detested things.)