Scholars of the Qur'ân have agreed about the meaning of this verse, though they express this meaning in different ways. Essentially, every day Allah is involved in countless matters:
He forgives sins. He removes difficulties. He raises some people in status and brings others low. This is how Abû al-Dardâ', the eminent Companion, explains it.
He creates from nothingness. He provides for His creation. He causes both life and death. He invests people with power and strips them of power. He restricts their circumstances and He liberates them. He does as He wills. This is the explanation of Ibn `Abbâs, another eminent Companion.
He raises children to maturity. He frees the prisoner. He enriches those who are in poverty. He fulfills the needs of the righteous. He is the focus of all their gratitude and their petitions. This is what Qatâdah says.
Abû al-Jawzâ' says: "One affair of His does not in any way distract Him from another."
What they all understand from this verse is that Allah is constantly involved in the act of Creation, and in the act of altering the circumstances of created things. He brings things into existence from nonexistence. He enriches the poor. He gives strength to the weak. He also brings about the opposites of these states, in all cases according to His infinite knowledge and wisdom.
As for Allah, He suffers no change within Himself. All changes, increases, decreases, alternations, and altered states – they are experienced by His creatures, in accordance with His divine will.
Allah says: "Say: O Allah! Owner of Sovereignty! You give sovereignty to whom You will, and withdraw sovereignty from whom You wilt. You exault whom you will, and abase whom You will. In Your hand is all good. Indeed, You are able to do all things. You the night to pass into the day, and the day to pass into the night. And Thou bring forth the living from the dead, and the dead from the living. And You give sustenance to whom You please without measure." [Sûrah Al `Imrân: 26-27]
The words we are looking at – "Every day, He carries out His will." – are part of a larger verse. The verse begins: "All those who are in the heavens and the Earth beseech Him." In other words all Creation: including its people, its angels, and its jinn.
This verse, then, is a great encouragement for us to beseech Allah in supplication for all of our needs. His bounty is indeed infinite. The verse implies, since it begins with mention of the entreaties and petitions of His creatures, that the changes Allah will bring about will be for the better. If they ask of Him, and if they beseech Him in earnest, then it is His nature to answer their petitions and to change their affairs for the better: form weakness to strength, from ignorance to knowledge, from backwardness to progress, from discord to unity.
This is the beautiful way in which the first part of the verse relates to the second. "All those who are in the heavens and the Earth beseech Him. Every day, He carries out His will."