What is the wisdom behind creating the earth in six days, when Allah Almighty says to a thing "Be," and it is; and how do we respond to those who claim that God became tired from creation, so He took Sunday as a day off?

The power of Allah Almighty is boundless; He creates what He wills, when He wills. Allah Almighty says: "Indeed, Our word to a thing when We intend it is only that We say to it, 'Be,' and it is." His creation of the heavens and the earth in six days was for purposes He intended, among them teaching His servants that gradualism is a universal principle. The trivial assertion made by the Jews — may Allah fight them — does not warrant a response after Allah Almighty's saying: "And We did certainly create the heavens and earth and what is between them in six days, and there touched Us no weariness," and weariness is lūghūb (fatigue).