When Our Ayat are recited to him, he says:
"Tales of the ancients!"
meaning, whenever he hears the Words of Allah from the Messenger , he denies it and has ill thoughts about it. Thus, he believes that it is a collection gathered from the books of the ancients.
This is as Allah says,
وَإِذَا قِيلَ لَهُمْ مَّاذَا 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 men of old!" (16:24)
Similarly Allah says,
وَقَالُواْ أَسَـطِيرُ الاٌّوَّلِينَ اكْتَتَبَهَا فَهِىَ تُمْلَى عَلَيْهِ بُكْرَةً وَأَصِيلً
And they say:
"Tales of the ancients, which he has written down: and they are dictated to him morning and afternoon." (25:5)
Then Allah continues saying,
كَلَّ بَلْ رَانَ عَلَى قُلُوبِهِم مَّا كَانُوا يَكْسِبُونَ