Ibn al-Qayyim said, “So it may become impossible for him to pronounce the shahaadah, as many people have witnessed happen to those on the deathbed, such that it was said to some of them:
“Say Laa ilaaha illallaah.” So he replied, “Aaah! Aaah! I cannot say it!”
And it was said to another, “Say Laa ilaaha illallaah.” So he replied, “King! Rook! Checkmate!” and then he passed away.
And it was said to another, “Say Laa ilaaha illallaah.” So he started singing irrationally, saying, ‘Taatinaa tinintaa, [no meaning, just irrational singing]’ and then passed away.
And the same was said to another, so he replied, “And how will what you are saying help me when I left no sin except that I committed it?” and then he passed away without saying it.
And the same was said to another, so he replied, “And how will that benefit me? And I don’t know if I have ever prayed a single time to Allaah?” and then he passed away without saying it.
And the same was said to another, so he replied [talking about himself], “He is a disbeliever in what you say,” and then he passed away.
And the same was said to another, so he replied, “Every time I want to say it my tongue withholds.”
And someone who was present at the death of someone who would beg told me that [they told him to say the shahaadah] so he started saying, “For Allaah’s Sake. A penny for Allaah’s Sake,” until he passed away.
And a trader told me that he was present when one of his relatives was on his deathbed, so they told him to say Laa ilaaha illallaah and he was saying, “This piece is cheap. This is a good buy. This is such and such,” until he passed away.
So if the devil has gained mastery over the servant in the state when his mind is present and his strength [is also present] and he has complete cognizance [i.e., while he is alive and healthy], and has employed him in committing whichever acts of disobedience to Allaah he wants him to do, and has made him unmindful of the remembrance of Allaah the Most High, and has paralysed his tongue from remembering Him and his limbs from obeying Him–then what does one think will be the case when his strength breaks down and his heart and soul become preoccupied with the death pangs that he is in?
And [all the while] Shaitaan will have gathered all of his strength and determination and assembled everything that he is capable of to avail his opportunity concerning him–for that is the last action.
So the strongest his Shaitaan will be against him is at that time, and the weakest he [i.e., the person] will be is at that time.
So who do you think will be safe from that? So it is there that, “Allaah keeps firm those who believe, with the firm word [i.e., ‘the firm word’ is Laa ilaaha illallaah], in the worldly life and in the Hereafter. And Allaah sends astray the wrongdoers. And Allaah does what He wills.” (Ibraaheem 14:27)
So how can someone whose heart Allaah has made heedless from His remembrance and who has followed his desires and whose affair is ever [in] neglect be granted the success to have a good ending?
Thus far away–the one whose heart is distant from Allaah the Most High, heedless of Him, worshipping his own desires, a slave to his lusts, his tongue dry from ever remembering Allaah [i.e., not moist with His remembrance], his limbs incapacitated from obeying Him actively working to disobey Him–far away [is such a person] from being granted the success to have a good ending.”
Ad-Daa wad-Dawaa, pp. 91-92.
…May Allah give us a better understanding & guide us to accept the truth