Surah Al-Qamar 54:8

مُّهْطِعِينَ إِلَى ٱلدَّاعِ ۖ يَقُولُ ٱلْكَـٰفِرُونَ هَـٰذَا يَوْمٌ عَسِرٌ

Racing ahead toward the Caller. The disbelievers will say, "This is a difficult Day."

Translation: Saheeh International

Tafsir

scrambling hastening with their necks stretched out toward the Summoner. The disbelievers among them will say ‘This is a hard day!’ a difficult one for disbelievers — as is stated in sūrat al-Muddaththir a day of hardship for the disbelievers Q. 749-10.

Excerpt from Tafsir al-Jalalayn, commentary on 54:8, via Quran.com. The reader has the full commentary and 9 more tafsirs.