Surah Ar-Rum 30:10

ثُمَّ كَانَ عَـٰقِبَةَ ٱلَّذِينَ أَسَـٰٓـُٔوا۟ ٱلسُّوٓأَىٰٓ أَن كَذَّبُوا۟ بِـَٔايَـٰتِ ٱللَّهِ وَكَانُوا۟ بِهَا يَسْتَهْزِءُونَ

Then the end of those who did evil was the worst [consequence] because they denied the signs of Allāh and used to ridicule them.

Translation: Saheeh International

Tafsir

Then the consequence for those who committed evil was evil al-sū’ā is the feminine form of al-aswa’ ‘the worst’; it may be read as the predicate of kāna if one reads ‘āqibatu in the nominative; or it is the subject of kāna if read as ‘āqibata in the accusative; …

Excerpt from Tafsir al-Jalalayn, commentary on 30:10, via Quran.com. The reader has the full commentary and 9 more tafsirs.