وَلَوْ أَنَّا أَهْلَكْنَاهُم بِعَذَابٍ مِّن قَبْلِهِ لَقَالُوا رَبَّنَا لَوْلَا أَرْسَلْتَ إِلَيْنَا رَسُولًا ...

And if We had destroyed them with a torment before this, they would surely have said: "Our Lord! If only You had sent us a Messenger...''

This means, "If We had destroyed these rejecting people before We sent this Noble Messenger to them and revealed the Mighty Book to them, they would have said, رَبَّنَا لَوْلَا أَرْسَلْتَ إِلَيْنَا رَسُولًا (Our Lord! If only You had sent us a Messenger), meaning, `before you destroyed us, so we could have believed in him and followed him.'

This is like Allah said,

... فَنَتَّبِعَ آيَاتِكَ مِن قَبْلِ أَن نَّذِلَّ وَنَخْزَى ﴿١٣٤﴾

we should certainly have followed Your Ayat, before we were humiliated and disgraced.

Allah, the Exalted, explains that these rejecters are stubborn and obstinate and they will not believe.

وَلَوْ جَآءَتْهُمْ كُلُّ ءايَةٍ حَتَّى يَرَوُاْ الْعَذَابَ الاٌّلِيمَ

Even if every sign should come them, until they see the painful torment. (10:97)

This is as Allah says,

وَهَـذَا كِتَـبٌ أَنزَلْنَـهُ مُبَارَكٌ فَاتَّبِعُوهُ وَاتَّقُواْ لَعَلَّكُمْ تُرْحَمُونَ

And this is a blessed Book which We have sent down, so follow it and have Taqwa (of Allah), that you may receive mercy. Until His statement, بِمَا كَانُواْ يَصْدِفُونَ (because of their turning away). (6:155-157)

Allah also says,

وَأَقْسَمُواْ بِاللَّهِ جَهْدَ أَيْمَـنِهِمْ لَئِن جَآءَهُمْ نَذِيرٌ لَّيَكُونُنَّ أَهْدَى مِنْ إِحْدَى الاٍّمَمِ

And they swore by Allah their most binding oath that if a warner came to them, they would be more guided than any of the nations (before them). (35:42)

وَأَقْسَمُواْ بِاللَّهِ جَهْدَ أَيْمَـنِهِمْ لَئِن جَآءَتْهُمْ ءَايَةٌ لَّيُؤْمِنُنَّ بِهَا

And they swear their strongest oaths by Allah, that if there came to them a sign, they would surely believe therein. (6:109) to the completion of those Ayat.

Then, Allah says,