The Angels were sent to destroy the People of the Prophet Lut

Allah the Exalted said about Ibrahim, peace be upon him,

فَلَمَّا ذَهَبَ عَنْ إِبْرَهِيمَ الرَّوْعُ وَجَآءَتْهُ الْبُشْرَى يُجَـدِلُنَا فِى قَوْمِ لُوطٍ - إِنَّ إِبْرَهِيمَ لَحَلِيمٌ أَوَّاهٌ مُّنِيبٌ - يإِبْرَهِيمُ أَعْرِضْ عَنْ هَـذَآ إِنَّهُ قَدْ جَآءَ أَمْرُ رَبِّكَ وَإِنَّهُمْ آتِيهِمْ عَذَابٌ غَيْرُ مَرْدُودٍ

(Then when the fear had gone away from (Ibrahim), and the glad tidings had reached him, he began to plead with Us for the people of Lut. Verily, Ibrahim was, without doubt forbearing, used to invoke Allah with humility, and was repentant. "O Ibrahim! Forsake this. Indeed, the commandment of your Lord has gone forth. Verily, there will come a torment for them which cannot be turned back.")(11:74-76) Allah said here,

قَالَ فَمَا خَطْبُكُمْ أَيُّهَا الْمُرْسَلُونَ

((Ibrahim) said: "Then for what purpose you have come, O messengers") meaning, `what is the mission that you were sent with,'

قَالُواْ إِنَّآ أُرْسِلْنَآ إِلَى قَوْمٍ مُّجْرِمِينَ

(They said: "We have been sent to a people who are criminals.") in reference to the people of Lut,

لِنُرْسِلَ عَلَيْهِمْ حِجَارَةً مِّن طِينٍ مُّسَوَّمَةً

(To send down upon them stones of baked clay, marked), or written,

عِندَ رَبِّكَ لِلْمُسْرِفِينَ

(by your Lord for transgressors.) recorded with Allah to their names; each stone has the name of its companion. Allah said in Surat Al-`Ankabut,

قَالَ إِنَّ فِيهَا لُوطاً قَالُواْ نَحْنُ أَعْلَمُ بِمَن فِيهَا لَنُنَجِّيَنَّهُ وَأَهْلَهُ إِلاَّ امْرَأَتَهُ كَانَتْ مِنَ الْغَـبِرِينَ

((Ibrahim) said: "But there is Lut in it." They said: "We know better who is there. We will verily save him and his family except his wife: she will be of those who remain behind.")(29:32), and said here,

فَأَخْرَجْنَا مَن كَانَ فِيهَا مِنَ الْمُؤْمِنِينَ

(So We brought out from therein the believers.) they are: Lut and his family, except his wife,

فَمَا وَجَدْنَا فِيهَا غَيْرَ بَيْتٍ مِّنَ الْمُسْلِمِينَ

(But We found not there any household of the Muslims except one.) Allah the Exalted said,

وَتَرَكْنَا فِيهَآ ءَايَةً لِّلَّذِينَ يَخَافُونَ الْعَذَابَ الاٌّلِيمَ

(And We have left there a sign for those who fear the painful torment.) meaning, `We left a proof of the punishment, torment and stones made of Sijjil (baked clay) that We sent on them; We made their dwelling place a putrid, evil, dead sea. This should provide a lesson for the believers,'

لِّلَّذِينَ يَخَافُونَ الْعَذَابَ الاٌّلِيمَ

(for those who fear the painful torment.)