People are asleep; when they die, they wake.
الناس نيام فإذا ماتوا انتبهوا
En-nâsü niyâmun fe-izâ mâtû intebehû.
Al-Ajluni, Kashf al-Khafa, no. 2794.
It is not a hadith. It is not in the Six Books; hadith scholars attribute the saying to Ali, while al-Sha'rani in his Tabaqat gives it to Sahl al-Tustari (al-Ajluni, Kashf al-Khafa, no. 2794). It is transmitted in the Sufi tradition; it has no chain of transmission reaching the Prophet.
The sleeper thinks, in his dream, that he is awake.
This is where the saying catches a person.
I go to work, I talk, I decide.
All of it happens inside a dream too.
Death is not mentioned here to frighten.
It becomes the measure of wakefulness.
The question turns to this:
Before dying,
how awake can one become?
You got up this morning.
Did you wake?