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 If We pleased We could take away what We have revealed to you. Then you will not find any one to plead for it with Us, 86 (Whatever you have received) is nothing but grace from your Lord. Indeed His favour to you is great. 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 We have explained things for people in this Qur'an in diverse ways to make them understand the Message, yet most people obstinately persist in unbelief. 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, let chunks of sky fall over us, as you assert (you will); or, bring God and the angels as a surety; 92 Or you should have a house of gold, or you should ascend into heaven, and we will not believe in your ascending until you bring down to us a book which we may read. Say: Glory be to my Lord; am I aught but a mortal apostle? 93