And they ask you (O Muhammad SAW) concerning the Ruh (the Spirit); Say: "The Ruh (the Spirit): it is one of the things, the knowledge of which is only with my Lord. And of knowledge, you (mankind) have been given only 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 [Thou art spared] only by thy Sustainer's grace: behold, His favour towards thee is great indeed! 87 Say, "If all men and jinn gathered together to produce the like of this Quran, they could not produce one like it, however much they helped 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 They declare, "We will never believe in you until you cause a spring to flow for us from the earth; 90 or that there be a garden of palms and vines for you and then you cause rivers to abundantly flow forth through 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 thou have a house [made] of gold, or thou ascend to heaven - but nay, we would not [even] believe in thy ascension unless thou bring down to us [from heaven] a writing which we [ourselves] could read! Say thou, [O Prophet:] "Limitless in His glory is my Sustainer! Am I, then, aught but a mortal man, an apostle?" 93