Allah says in Surah al-Mulk:
"Whether you keep your words secret, or declare them—He is Aware of the inner thoughts." (Verse 13)
Commentators comment on the reason for the revelation of this verse: Some of the disbelievers say in their conversations when speaking against Muhammad peace be upon him, "Speak quietly, and let the God of Muhammad not hear." This is how the Quran refutes their narrow minding.
This notion that Allah knows all the secrets, including all that is in the heart, causes the heart to fear the Almighty. This, as we have already said, encourages avoiding all sin.
"Would He not know, He Who created? He is the Refined, the Expert." (Verse 14)
If a weak man invents a device, he knows all the details, the deficiency, how it works, when it will be corrupted and indeed does the Creator of all things not know the state of His servants?
"It is He who made the earth manageable for you, so travel its regions, and eat of His provisions. To Him is the Resurgence." (Verse 15)
Our scholars have long ago cited this ayah as an indication of the need to work in Islam, eating sustenance with labor and acting in various parts of the world. Indeed, Allah made the earth submissive to man, but this fact has never been more evident than in our time. Man has done all sorts of land use. The phrase "walk" in this verse always motivates Muslims to take up professions and to avoid laziness and idleness. At the same time, it is necessary to remember that sustenance comes from Allah. After the above verse has been shown to be a blessing to human beings, the following verse reveals the consequences of ungratefulness and the fact that the earth, which submits to human beings, can be shattered and may swallow up.