Al Bukhari said: “Salim said: “The word “al-jakeen” means death”. This said Mujaheed, Al Hassan, Qatada and others.
This the proof what the Lord said, informing us:
|“They will say: “We were not of those who used to offer the Salat (prayers),|
|“Nor we used to feed Al-Miskin (the poor);|
|“And we used to talk falsehood (all that which Allah hated) with vain talkers.|
|And we used to belie the Day of Recompense,|
|“Until there came to us (the death) that is certain.” surah 74 verse 43-47.|
Here’s to mention, the failure that some sufis make, by saying the “al-jaqeen” means cognition, and when someone of them reaches the level of cognition, the they stop worshipping Allah s.w.t, and that’s kufr, ignorance and delusion. Summary of Ibn Kathir’s Tafsir