Every time a group is cast therein, its keepers will ask: "Did no warner come to you"
They will say: "Yes, indeed a warner did come to us, but we rejected him and said: `Allah never sent down anything; you are only in great error."'
In these Ayat Allah reminds of His justice in dealing with His creatures and that He does not punish anyone until the proof has been established against them and a Messenger has been sent to them.
This is similar to Allah's statement,
وَمَا كُنَّا مُعَذِّبِينَ حَتَّى نَبْعَثَ رَسُولاً
And We never punish until We have sent a Messenger. (17:15)
Allah also says,
حَتَّى إِذَا جَأءُوهَا فُتِحَتْ أَبْوَبُهَا وَقَالَ لَهُمْ خَزَنَتُهَأ أَلَمْ يَأْتِكُمْ رُسُلٌ مِّنكُمْ يَتْلُونَ عَلَيْكُمْ ءَايَـتِ رَبِّكُمْ وَيُنذِرُونَكُمْ لِقَـأءَ يَوْمِكُمْ هَـذَا قَالُواْ بَلَى وَلَـكِنْ حَقَّتْ كَلِمَةُ الْعَذَابِ عَلَى الْكَـفِرِينَ
till when they reach it, the gates thereof will be opened. And its keepers will say, "Did not the Messengers come to you from yourselves, reciting to you the Ayat of your Lord, and warning you of the meeting of this Day of yours"
They will say: "Yes," but the Word of torment has been justified against the disbelievers!" (39:71)
Thus, they have no recourse but to blame themselves and they will feel remorseful when such remorse will be of no benefit to them.