17. The Messengers posed this question to those who rejected the message in order to bring home to them the absurdity of their stand with regard to God. For though, the mushriks of every age believed in the existence of God and acknowledged that He was the Creator of the heavens and the earth, they did not accept the message, its logical result, that He alone was entitled to their worship. That is why the Messengers asked them: Do you have any doubt about the existence of Allah?
18. In the case of individuals, the appointed term may be either the time of one’s death or the doomsday. As regards the appointed term for the rise and fall of communities, it is determined by their collective behavior. For instance, if a capable community degenerates before the expiry of its term, the assigned period is shortened and it is deposed. On the other hand, if a degenerate community changes its ways for the better, its term is extended, so much so that it may extend even to the doomsday. This same thing is implied in (Ayat 11 of Surah Ar-Raad): The fact is that Allah does not change a people’s lot unless they themselves change their own characteristics.
19. The disbelievers meant to imply: You are a human being like us in every respect: you eat, drink and sleep like us and have wife and children like us. You feel hungry and thirsty, and suffer from heat and cold, disease and calamities like us. In short, you have every human limitation like us, and we see nothing unusual and extraordinary in you to induct us to accept you as a Prophet and believe that God communicates with you and sends His angels to you.
19. The disbelievers meant to imply: You are a human being like us in every respect: you eat, drink and sleep like us and have wife and children like us. You feel hungry and thirsty, and suffer from heat and cold, disease and calamities like us. In short, you have every human limitation like us, and we see nothing unusual and extraordinary in you to induct us to accept you as a Prophet and believe that God communicates with you and sends His angels to you.
20. That is, if you still insist that you are a Prophet, bring a tangible proof of your appointment so as to convince us that you have really been sent by God and your message is from Him.