[18].Surah Al-Kahf [The Cave]: Ayat 39-41

Ayat 39. It was better for you to say, when you entered your garden: 'That which Allah wills (will come to pass)! There is no power but with Allah '. If you see me less than you in wealth, and children.

Ayat 40. "It may be that my Lord will give me something better than your garden, and will send on it Husbân (torment, bolt, etc.) from the sky, then it will be a slippery earth.

Ayat 41. "Or the water thereof (of the gardens) becomes deep-sunken (underground) so that you will never be able to seek it."

[Tafseer] (If only, when thou enteredst thy garden, thou hadst said: That which Allah wills (will come to pass)!) this is from Allah and not from me. (There is no strength save in Allah!) this is only through Allah's power, not through my own power. (Though thou sees me as less than you in wealth and children) and servants in the life of this world. (Yet it may be) 'may be' when used in connection to Allah denotes a requisite (that my Lord will give me) in the Hereafter (better than your garden) in the life of this world, (and will send on it) on your garden (a bolt) of fire (from heaven, and some morning it will be a smooth hillside) smooth dust, (Or some morning the water thereof) the water of the garden (will be lost in the earth) will sink in the earth, out of reach (so that thou canst not make search for it) so that you cannot access it.  

Hazrat Abu Sa`id Al-Khudri and Abu Hurairah (May Allah be pleased with them) reported: The Messenger of Allah [SAWW](PBUH) said, "If a person says: `La ilaha illallahu wallahu Akbar (There is no true god except Allah and Allah is Greatest)', his Rubb responds to him and affirms: `(Yes!) There is no true god except I, and I am the Greatest.' When he says: `La ilaha illallahu Wahdahu la sharika Lahu (There is no true god except Allah, the One, He has no partner).' Allah (SWT) affirms: `(Yes!) There is no true god except I. I have no partner.' When he says: `La ilaha illallahu Lahul mulku wa Lahul-hamdu (the sovereignty belongs to Him and all the praise is due to Him).' He (SWT) affirms: `(Yes!) There is no true god except I, Mine is the praise and to Me belongs the sovereignty.' When he says: `La ilaha illallahu wa la hawla wa la quwwata illa Billah (There is no true god except Allah, and there is no might and power but with Allah).' He (SWT) affirms: `(Yes!) There is no true god except I, and there is no might and power but with Me.''' The Messenger of Allah (PBUH) added, "He who recites this during his illness and dies, will not be touched by the Fire (Hell).''

[At-Tirmidhu Hadith # 3430]. 

Lesson : as mentioned above in Surah Al-Kahf Ayat 39. "That which Allah wills (will come to pass)! There is no power but with Allah" This Hadith points out the excellence of the words mentioned above. This is so because of great meaning they have, namely the firm belief in Allah, His Oneness and Glorification; that to Him Alone we should return, upon Him Alone we should rely, and to Him Alone we should express gratefulness. If somebody utters them during his illness, his life is sure to come to an end in a good way, that is, he will go to Jannah.