(Lut said: "Verily, these are my guests, so do not shame me. And have Taqwa of Allah, and do not disgrace me.") This is what Lut said to them before he knew that his guests were messengers from Allah, as mentioned in Surat Hud, but here (in this Surah), we have already been told that they are messengers from Allah, and this is followed by an account of Lut's people coming and his exchange with them. However, here the conjunction (wa, meaning "and") does not imply the sequence of events, especially since there is something to indicate that this is not the case. They said answering him,
From verse 48: لَا يَمَسُّهُمْ فِيهَا نَصَبٌ وَمَا هُم مِّنْهَا بِمُخْرَجِينَ (No weariness shall touch them therein nor will they be expelled from there), we learn about two features of Jannah: (1) No one shall ever feel tired or weak. This is contrary to what happens in our mortal world where hard work naturally results in fatigue. In fact, even a state of total rest and fun would sometimes tire a person out, no matter how enjoyable are things one is occupied with. (2) The other feature of Jannah we discover is that the blessings once received there shall be eternal. These blessings shall never diminish nor shall anyone be expelled from there. In Surah Sad, it was said:إِنَّ هَـٰذَا لَرِزْقُنَا مَا لَهُ مِن نَّفَادٍ (This is sustenance provided by Us which is never to exhaust - 38:54). And in the present verse, it was said: وَمَا هُم مِّنْهَا بِمُخْرَجِينَ (nor will they be expelled from there) that is, they shall never be deprived of the state of bliss bestowed upon them. This is contrary to the affairs of the mortal world where the recipient of the best of conveniences lives under the apprehension that the Over of the facilities may become displeased with him one of those days and expel him out.
The angels who went to the town of Lot’s community took the shape of extremely handsome youths. This was like the last examination paper to test this community which was steeped in debauchery. In their overweening arrogance, they made a rush towards these youths with the intention of molesting them, as usual. But they did not know that those they looked upon as charming youths were, in fact, the angels of punishment who had come only to leave them disgraced and dishonoured.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.