وَما أَدراكَ ما سِجّينٌ

And what will show you what is sijjīn?

EXEGESIS

Adrā is the transitive form from the root darā which means to comprehend, to grasp, and to reach and attain the depth of something.^{‎[1]Raghib, p. 312.} So, adrā means to make understand, to make perceive, or attain the uttermost knowledge of a thing. The rhetorical question mā adrāka (what will show you) is a style the Quran uses in many places to express amazement at the unfathomable reality of something which is beyond easy human comprehension.

REVIEW OF TAFSĪR LITERATURE

Ṭabrisī believes that the rhetorical question And what will show you what is sijjīn is used to indicate that sijjīn is something neither the Prophet nor Arabs at the time understood.^{‎[2]Tabrisi, 10/688.} However, Rāzī says that sijjīn signifies lowness, degradation, darkness, restriction, and the presence of demons.^{‎[3]Razi, 31/86.}

[1] Raghib, p. 312.
[2] Tabrisi, 10/688.
[3] Razi, 31/86.