Have you not seen how the ships sail on the sea by God's grace so that He may show you some of His signs? Surely therein are signs for every steadfast, thankful person. 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 coming of the Hour of Doom. He sends down the rain and knows what is in the wombs. No soul is aware of what it will achieve tomorrow and no soul knows in which land it will die. God is All-knowing and All-aware. 34