It is a subject with a missing predicate according to Sibawayh. Its meaning is: And in what He narrates to you is the example of those who disbelieved in their Lord. The example is borrowed for the description that contains strangeness. And His saying, "Their deeds are like ashes," is a statement that follows the assumption of a questioner asking: How is their example? It was said: Their deeds are like ashes. It is also possible that the meaning is: The example of the deeds of those who disbelieved in their Lord. Or this sentence is a predicate for the subject, meaning the description of those who disbelieved: Their deeds are like ashes, as you would say: The description of Zayd is that his honor is protected and his wealth is abundant. Or the deeds of theirs could be a substitute for the example of those who disbelieved, assuming: The example of their deeds, and "like ashes" is the predicate. And it was read: The winds in a stormy day, attributing the storm to the day, which is because of it, which is the wind or the winds, as you would say: A rainy day and a calm night. And the calmness is for its wind. And it was read: On a stormy day, in addition. And the deeds of the disbelievers are the noble acts they had, such as maintaining family ties, freeing captives, redeeming prisoners, slaughtering camels for guests, aiding those in distress, granting permission, and other acts of theirs. Their deeds are likened in their nullification and disappearance to scattered dust, as they are built on no foundation of knowledge of Allah and faith in Him, and for His sake: Like ashes blown away by the stormy wind. They will not be able on the Day of Resurrection to gain anything from what they earned of their deeds, meaning they will not see any trace of reward for them, just as one cannot gain anything from ashes blown in the wind. That is the far astray, indicating the distance of their misguidance from the path of truth or from the reward of truth with wisdom and the correct purpose. And the great matter was not created in vain or out of desire.