Surah 101. Al-Qariah, Ayah 9

Lit., "his mother [i.e., goal] will be an abyss", sc., of suffering and despair. The term "mother" (umm) is used idiomatically to denote something that embraces or enfolds.

Just as grades of bliss are indicated for the righteous, so apparently we are to understand grades of punishment suited to the sins of the individual sinners concerned.