Because existence has a purpose
Humanity was not created in vain and will not be left without account. The Quran answers the question of purpose plainly: we were created to know God and worship Him, and this life was made an arena of testing and deeds.
“And I did not create the jinn and mankind except to worship Me.”Because mercy requires clarity
A Creator who brings His servants into existence and then abandons them in confusion, with no map — that picture does not befit the perfection and mercy of God. Sending messengers and revealing books is what divine mercy entails: the path made clear, and no excuse left before the reckoning.
“And We have not sent you except as a mercy to the worlds.”Because humanity needs a fixed measure
Societies swing between extremes, and every generation redefines good and evil to its own liking. The Quran came to be the fixed measure that guides to what is most upright — in belief, in character, and in dealings.
“Indeed, this Quran guides to that which is most upright.”And because a test requires freedom
God sent down the clarification, then left the human being free to choose — because the value of faith lies in its being a choice. This worldly life is the field of deeds; the hereafter is the abode of recompense.
“He who created death and life to test you as to which of you is best in deed.”