It is He who made the earth submissive to you; therefore walk in its tracts, and eat of His provision; to Him is the Uprising. 15 Do you feel secure that He who is in heaven will not cause the earth to swallow you, the while it rocks? 16 Do you feel secure that He Who is in the heaven will not let loose upon you a storm of stones? Then shall you know what My warning is like! 17 Those who lived before them had also rejected Our warning, and how terrible was Our retribution! 18 Have they not regarded the birds above them spreading their wings, and closing them? Naught holds them but the All-merciful. Surely He sees everything. 19 Or which army do you have that will help you against the Most Gracious? The disbelievers are in nothing except an illusion. 20 Or who is such that will give you sustenance if Allah stops His sustenance? In fact they persist in rebellion and hatred. 21 Can one who walks with his head hanging down be better guided that one who walks with his head upright? 22 Say: 'It is He who has created you and given to you hearing, sight and hearts but little is it that you thank' 23 Say: He it is Who multiplieth you in the earth, and unto Whom ye will be gathered. 24 But they say: "When will this promise come to pass, if what you say is true?" 25 Say thou, [O Prophet:] "Knowledge thereof rests with God alone; and I am only a plain warner." 26 Then, when they see it drawing near, the faces of the unbelievers will be blackened, and it is said: 'This is what you were promised' 27 Say: 'What think you? If God destroys me and those with me, or has mercy on us, then who will protect the unbelievers from a painful chastisement?' 28 Say, "He is the Most Merciful; we have believed in Him, and upon Him we have relied. And you will [come to] know who it is that is in clear error." 29 Say thou: bethink ye, were your water to be sunk away, who then could bring you water welling-up? 30