This is not but the custom of the former peoples, (26:137)

Almuntakhab Fi Tafsir Alquran Alkarim

This is nothing, they said, other than the customary manner of thinking of those of old used often enough that it bred the same habit in you

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(26:137) such things have been said in the past as well, *93

This is not but the custom of the former peoples, meaning

*93) This can have two meanings: (1) "Whatever we are doing is not new but has been happening from the tune of our elders since centuries: they had the same creed, the same way of life, the same morality and the same kind of dealings and yet they remained unharmed and safe from every calamity. If there was any evil in this way of life, we should have met the doom with which you are threatening us." (2) "The things you are preaching have been preached and said before also by religious maniacs and so-called moralists, but they could not change the ways of the world. It has never happened that the world suffered a disaster only because people refused to listen to preachers like you."
 

This is not but the custom of the former peoples, meaning in Urdu

یہ باتیں تو یوں ہی ہوتی چلی آئی ہیں