Have you not seen that the ships sail in the ocean through the bounty of God so that He may show you the evidence (of His existence). There is evidence (of the truth) in this for every forbearing and grateful one. 31 When waves engulf them (in the sea) like canopies, they call upon Allah, consecrating their faith solely to Him. But when He delivers them safely to the land, some of them become lukewarm. None denies Our Signs except the perfidious, the ungrateful. 32 O mankind! do your duty to your Lord, and fear (the coming of) a Day when no father can avail aught for his son, nor a son avail aught for his father. Verily, the promise of Allah is true: let not then this present life deceive you, nor let the chief Deceiver deceive you about Allah. 33 Only God has the knowledge of the Hour. He sends rain from the heavens, and knows what is in the mothers' wombs. No one knows what he will do on the morrow; no one knows in what land he will die. Surely God knows and is cognisant. 34