﴿ إِنَّهَا لَإِحْدَى ٱلْكُبَرِ ﴾

“Verily, that [hell-fire) is Indeed one of the great [forewarnings] –”

Lo! this is) i.e. Saqar (one of the greatest (portents)) this is one of the gates of the Fire; other gates include: Jahannam, Laza, al-Hutamah, al-Sa'ir, al-Jahim, and al-Hawiyah.