Surah Ash-Shu'ara 26:137

إِنْ هَـٰذَآ إِلَّا خُلُقُ ٱلْأَوَّلِينَ

This is not but the custom of the former peoples,

Translation: Saheeh International

Tafsir

This that you threaten us with is merely the fabrication of the ancients that is their inventions and lies a variant reading for khalq ‘fabrication’ is khuluq ‘ethos’ in other words this denial of resurrection to which we adhere is merely ‘the ethos of the ancients’ in other words their nature and wont;

Excerpt from Tafsir al-Jalalayn, commentary on 26:137, via Quran.com. The reader has the full commentary and 9 more tafsirs.