You are reading a tafsir for the group of verses 46:26 to 46:28
وَجَعَلْنَا لَهُمْ سَمْعاً وَأَبْصَـراً وَأَفْئِدَةً فَمَآ أَغْنَى عَنْهُمْ سَمْعُهُمْ وَلاَ أَبْصَـرُهُمْ وَلاَ أَفْئِدَتُهُمْ مِّن شَىْءٍ إِذْ كَانُواْ يَجْحَدُونَ بِـَايَـتِ اللَّهِ وَحَاقَ بِهم مَّا كَانُواْ بِهِ يَسْتَهْزِءُونَ

(We also gave them hearing, vision, and hearts. But their hearing, vision, and hearts availed them nothing when they used to deny Allah's signs, and they were completely encircled by that which they used to ridicule!) meaning, they were encircled by the torment and exemplary punishment that they denied and whose occurrence they doubted. This means, you listeners must beware of being like them lest a punishment similar to theirs strikes you in this life and the Hereafter. Allah then says,

وَلَقَدْ أَهْلَكْنَا مَا حَوْلَكُمْ مِّنَ الْقُرَى

(And indeed We have destroyed towns round about you, ) This is addressed to the people of Makkah. Allah destroyed the nations who disbelieved in the Messengers who lived around Makkah, such as `Ad who were at Al-Ahqaf in Hadramawt near Yemen, Thamud whose dwellings were between Makkah and Ash-Sham (Greater Syria), Saba' who were in Yemen, the people of Madyan who were on the route and passage to Ghazzah (Western Palestine), and the people of Lut who dwelt by the lake (the Dead Sea) which they used to pass by (on the way to Jordan) as well. Allah then says,

وَصَرَّفْنَا الاٌّيَـتِ

(and We have shown (them) the signs in various ways) meaning, `We explained and clarified them.'

لَعَلَّهُمْ يَرْجِعُونَفَلَوْلاَ نَصَرَهُمُ الَّذِينَ اتَّخَذُواْ مِن دُونِ اللَّهِ قُرْبَاناً ءَالِهَةَ

(so that perhaps they might return. As for those whom they had taken for gods besides Allah, as the means of approach to Him, why then did they not aid them) meaning, did they help them when they were in the greatest need for them

بَلْ ضَلُّواْ عَنْهُمْ

(but they vanished completely from them.) Rather, they completely left them alone when they needed them the most.

وَذَلِكَ إِفْكُهُمْ

(And that was their falsehood, ) meaning, their lie.

وَمَا كَانُواْ يَفْتَرُونَ

(and what they were fabricating.) which means that they fabricated lies by taking them as gods, and they lost and failed in their worship of them and their reliance upon them -- and Allah knows best.