What are divine decree (Qada’) and destiny (Qadar), and do they change? Why are we asked to supplicate (du'a) even though everything is already written? And what is the meaning of "The pens have been lifted and the pages have dried"?

The hadith: "The pens have been lifted and the scrolls have dried" means that what has been written in the Preserved Tablet concerning decrees has been finalized, and nothing more will be written thereafter. This is a simile for the precedence of divine decree and destiny over what will occur. Evidence for this has been presented, such as the Almighty’s saying: "No disaster strikes upon the earth or among yourselves except that it is in a register before We bring it into being" and His saying: "Say, 'Nothing will ever befall us except what Allah has decreed for us.'"

Supplication (du'a) has a great effect in averting affliction. Scholars have mentioned that it is prescribed to supplicate for the removal of affliction and the repelling of decree. Decree is divided into two types: Mubram (absolute) and Mu'allaq (contingent). The mubram decree does not change, whereas the mu'allaq decree may change through supplication and certain righteous deeds, such as maintaining kinship ties, in confirmation of the hadith: "Nothing averts divine decree except supplication."

Supplication is an act of worship in which the supplicant will always find good. Either their need will be fulfilled sooner or later, or an equivalent amount of harm will be averted from them.