Surah Al-Muddaththir 74:17
سَأُرْهِقُهُۥ صَعُودًا
I will cover him with arduous torment.
Translation: Saheeh International
Tafsir
Soon I shall burden him with a trying chastisement; alternatively sa‘ūdan means a mountain of fire which he will be made to ascend and then fall down from forever.
Excerpt from Tafsir al-Jalalayn, commentary on 74:17, via Quran.com. The reader has the full commentary and 9 more tafsirs.