And they said:

إِنْ هَذَا إِلَّا خُلُقُ الْأَوَّلِينَ ﴿١٣٧﴾

This is no other than Khuluq of the ancients.

Some scholars read this: "Khalq''.

According to Ibn Mas`ud and according to Abdullah bin Abbas -- as reported from Al-Awfi -- and Alqamah and Mujahid, they meant,

"What you have brought to us is nothing but the tales (Akhlaq) of the ancients.''

This is like what the idolators of Quraysh said:

وَقَالُواْ أَسَـطِيرُ الاٌّوَّلِينَ اكْتَتَبَهَا فَهِىَ تُمْلَى عَلَيْهِ بُكْرَةً وَأَصِيلاً

And they say: "Tales of the ancients, which he has written down, and they are dictated to him morning and afternoon.'' (25:5)

And Allah said:

وَقَالَ الَّذِينَ كَفَرُواْ إِنْ هَـذَا إِلاَّ إِفْكٌ افْتَرَاهُ وَأَعَانَهُ عَلَيْهِ قَوْمٌ ءَاخَرُونَ فَقَدْ جَآءُوا ظُلْماً وَزُوراً

وَقَالُواْ أَسَـطِيرُ الاٌّوَّلِينَ ...

Those who disbelieve say: "This is nothing but a lie that he has invented, and others have helped him in it. In fact, they have produced an injustice and a lie.''

And they say: "Tales of the ancients...'' (25:4-5)

وَإِذَا قِيلَ لَهُمْ مَّاذَآ أَنزَلَ رَبُّكُمْ قَالُواْ أَسَـطِيرُ الاٌّوَّلِينَ

And when it is said to them: "What is it that your Lord has sent down''

They say: "Tales of the ancient!'' (16:24)

Some other scholars recited it, إِنْ هَذَا إِلَّا خُلُقُ الْأَوَّلِينَ (This is no other than Khuluq of the ancients), "as Khuluq,''

meaning their religion.

What they were following was the religion of the ancients, their fathers and grandfathers, as if they were saying:

"We are following them, we will live as they lived and die as they died, and there will be no resurrection and no judgement.''