Bukhari

Hadith Commentary:

You were afflicted with such an intense fever that even the blessed cloak became extremely hot. Repeatedly, unconsciousness would overcome you; you would lose consciousness and then regain it, and then again unconsciousness would set in. In moments of consciousness, these words would flow from your blessed tongue: (Allahumma alhiqni bil-rafiq al-a‘la. Sallallahu alayhi wa sallam).

Hadith Commentary:
(1)
Aisha radi Allahu anha describes the state of the Prophet sallallahu alayhi wa sallam during his final illness: he would fall unconscious, then regain consciousness, moisten a cloth with water and place it on his lips, and say:
Death has many severe agonies.

(2)
Allah ta'ala subjects those individuals to severe hardships who possess strong certainty, perfect patience, and very firm faith.
They consider illness to be a means of attaining reward and elevation of ranks; therefore, the more severe the illness, the greater the reward will be.
Wallahu al-musta‘an.

Explanation:
1:
This refers to the hardship which the Prophet (sallallahu alayhi wa sallam) faced during his final illness.

Benefit:
The severity or ease of the soul’s departure is one matter.
And the pain felt in the body due to illness is another matter.
Sometimes, due to the intensity of the illness, the pain remains until death.
This is physical pain.
It has no connection to whether a person is righteous or wicked.
The pain that is experienced due to the severity of the angels at the time of the soul’s departure is related to the soul.
Those sitting nearby cannot perceive this pain; however, this pain does not occur to the righteous.
For sinners and disbelievers, it occurs in lesser or greater degree according to their crimes.