"With Him are the keys of the unseen, the treasures that none knoweth but He. He knoweth whatever there is on the earth and in the sea. Not a leaf doth fall but with His knowledge: there is not a grain in the darkness (or depths) of the earth, nor anything fresh or dry (green or withered), but is (inscribed) in a record clear (to those who can read)."
 

(Holy Qur'an (Yusufali) 6:59)

"It is He who doth take your souls by night, and hath knowledge of all that ye have done by day: by day doth He raise you up again; that a term appointed be fulfilled; In the end unto Him will be your return; then will He show you the truth of all that ye did."
 

(Holy Qur'an (Yusufali) 6:60)

"He is the irresistible, (watching) from above over His worshippers, and He sets guardians over you. At length, when death approaches one of you, Our angels take his soul, and they never fail in their duty."
 

(Yusufali) 6:61)

"Hear me once again that this world is perishable and destructible, its phases change quickly, often leaving nothing but sad lessons behind them. A proof of mortality of everything in this world is the fact that there is destruction and decay everywhere, calamities attack everyone without missing a chance and sorrows visit without allowing a single chance of escape; here every living being shall have to pass through the doors of death, every healthy person shall have visitations of disease, and every happy individual shall have to face sorrows some time or other. In its desire for destruction, this world behaves like a glutton whose hunger is never-satisfied or like a drunkard whose thirst is never quenched.
 
Of sorrows and unrelenting severeness (harshness), it is enough to visualize that those who amass wealth seldom enjoy it, those who build homes rarely live in them. They always leave this world in such a way that they cannot carry their wealth and property with them. The sharp, sudden and violent changes of circumstances in life are sights to take lessons from. We find have-nots becoming so rich that they are envied, and millionaires turning paupers overnight because of disappearance of wealth and visitation of afflictions. There are enough warnings about us, if only we look carefully around and see persons on the door of success being visited suddenly by death, which neither spares the desirer nor allows the tidings of success to reach him.
 
Glory be to God! How alluring and delusive are the pleasures of this world; how every enhancement and increase in wealth and position here increases greed and avariciousness (immoderate desire for wealth or gain); and how the protection offered here very often ends in punishment and pain; what a place is it where neither death can be averted nor the past can be brought back. Good God! How near are living things to dead because of the fact of approach of death towards them, and how far apart they are from each other because they cannot on their own accord contact those who have ceased to exist."
 

(Nahjul Balagha: Sermons, letters and saying of Hazrat Ali (Second American edition, 1981), Khutba 117, p. 87)