Tafsir of Al-Muddathir 74:26

Al-Muddaththir (The Cloaked One): Verse 26

سأصليه سقر

I will admit him to Saqar.

Commentary:

Ibn Abbas (may Allah be pleased with him) said:

• {Saqar} is the name of the sixth layer (or level) of Hellfire.
• This is why it is diptote (does not take the tanwin ending), due to it being both a proper noun (for identification) and feminine in nature.

Then He said:

ومآ أدراك ما سقر

And what will make you know what Saqar is?