The request of the Meccan polytheists to bring tangible/concrete evidence

And say: "We will not believe you until you make a spring of water gush forth from the earth for us;

Or, until you acquire an orchard of date-palm trees and grapes, and produce rivers flowing through it;

Or, let chunks of sky fall over us, as you assert (you will); or, bring God and the angels as a surety;

Or, you come to possess a house of gold; or ascend to the skies, though we shall not believe in your having ascended till you bring down a book for us which we could read." Say: "Glory to my Lord. I am only man and a messenger."