And they ask thee regarding the spirit; say thou: the spirit is by the command of my Lord, and ye have not been vouchsafed of knowledge save a little. 85 And if We willed We could withdraw that which We have revealed unto thee, then wouldst thou find no guardian for thee against Us in respect thereof. 86 Except as a mercy from thy Lord verily His grace unto thee is ever great. 87 Say thou: if the mankind and the jinn leagued together that they might produce the like of this Qur'an, they could nor produce the like thereof, though one to the other were a backer. 88 Indeed, We have set forth for mankind in this Koran every kind of parable, yet most people refuse all except disbelief. 89 And say: "We will not believe you until you make a spring of water gush forth from the earth for us; 90 Or, until you acquire an orchard of date-palm trees and grapes, and produce rivers flowing through it; 91 or cause the sky to fall into pieces on us - as you believe you can - or bring God and the angels face to face with us, 92 Or you have a house of gold or you ascend into the sky. And [even then], we will not believe in your ascension until you bring down to us a book we may read." Say, "Exalted is my Lord! Was I ever but a human messenger?" 93