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 listed, We could surely take away that which We have revealed unto thee; then thou wilt not find in respect thereof against Us as trustee. 86 But on account of mercy from your Lord-- surely His grace to you is abundant. 87 Say: "If all mankind and all invisible beings would come together with a view to producing the like of this Qur'an, they could not produce its like even though they were to exert all their strength in aiding one another!" 88 Indeed, We have set forth for mankind in this Koran every kind of parable, yet most people refuse all except disbelief. 89 and so they say: "[O Muhammad,] we shall not believe thee till thou cause a spring to gush forth for us from the earth, 90 or you have a garden of date palms and vines, and cause streams to flow plentifully in the midst of them; 91 or till thou makest heaven to fall, as thou assertest, on us in fragments, or thou bringest God and the angels as a surety, 92 or, until you possess an ornate house of gold, or ascend into the heavens; and we will not believe in your ascension until you have brought down for us a book which we can read' Say: 'Exaltations to my Lord! Am I anything except a human Messenger' 93