Why did God create this world and the Hereafter when He already knew in advance who would be a believer and who would be an infidel?

Allah created the worldly life for trials, as He Almighty said: (He who created death and life to test you—which of you is best in deed). Whoever believed in the messengers and acted according to the scriptures would be among the people of Paradise, and whoever disbelieved would be among the wretched. The Prophet, peace and blessings be upon him, was asked whether people's actions were a predetermined matter or a new one, and he said: "Rather, it is a matter that has been decreed and concluded." And he said: "Act, for everyone is facilitated for that for which he was created." Allah Almighty said: (Indeed, your efforts are diverse). One must work, seek guidance, and pray for steadfastness, knowing that Allah created creation and He knows their provisions, their lifespans, and their deeds. One must trust in Allah's wisdom and justice, submit to His command, and recognize that any incapacity or flaw lies in our understanding, not in Allah's wisdom.