Allah states here that the people of Thamud denied their Messenger Salih,

فَقَالُواْ أَبَشَراً مِّنَّا وَحِداً نَّتَّبِعُهُ إِنَّآ إِذاً لَّفِى ضَلَـلٍ وَسُعُرٍ

(And they said: "A man, alone among us -- shall we follow him Truly, then we should be in error and distress!") They said, `We would have earned failure and loss if we all submitted to a man from among us.' They were amazed that the Reminder was sent to him alone among them, and therefore, accused him of being a liar,

بَلْ هُوَ كَذَّابٌ أَشِرٌ

(Nay, he is an insolent liar!), means, he has tresspassed the limits in his lies. Allah the Exalted responded,

سَيَعْلَمُونَ غَداً مَّنِ الْكَذَّابُ الاٌّشِرُ

(Tomorrow they will come to know who is the liar, the insolent one!), thus warning and threatening them and delivering a sure promise to them,

إِنَّا مُرْسِلُواْ النَّاقَةِ فِتْنَةً لَّهُمْ

(Verily, We are sending the she-camel as a test for them.) To test and try the people of Thamud, Allah sent to them a superb, pregnant female camel that emerged from solid rock, according to their request, so that it would become a proof against them from Allah, the Exalted. Thereafter, they were supposed to believe in what was brought to them by Salih, peace be upon him. Allah ordered His servant and Messenger Salih,

فَارْتَقِبْهُمْ وَاصْطَبِرْ

(So watch them, and be patient!) Allah commanded, `await, O Salih, and see what will become of them and be patient; verily the better end will be yours and you will have success in this life and the Hereafter,'

وَنَبِّئْهُمْ أَنَّ الْمَآءَ قِسْمَةٌ بَيْنَهُمْ

(And inform them that the water is to be shared between them) one day for her to drink and one day for them to drink,

قَالَ هَـذِهِ نَاقَةٌ لَّهَا شِرْبٌ وَلَكُمْ شِرْبُ يَوْمٍ مَّعْلُومٍ

(He said: "Here is a she-camel: it has a right to drink, and you have a right to drink (water) on a day, known.") (26:155) Allah's statement,

كُلُّ شِرْبٍ مُّحْتَضَرٌ

(each one's right to drink being established.) Mujahid said, "When she did not drink, they would drink the water, and when she drank, they would drink her milk." Allah the Exalted said;

فَنَادَوْاْ صَـحِبَهُمْ فَتَعَاطَى فَعَقَرَ

(But they called their comrade and he took and killed.) According to the Scholars of Tafsir, his name was Qudar bin Salif; he was the evilest among them,

إِذِ انبَعَثَ أَشْقَـهَا

(When the most wicked man among them went forth (to kill the she-camel).)(91:12) Allah said here,

فَتَعَاطَى

(and he took) meaning to harm,

فَعَقَرَفَكَيْفَ كَانَ عَذَابِى وَنُذُرِ

(and killed (her). Then, how was My torment and My warnings), `I tormented them, so how was the torment I sent on them because of their disbe- lief in Me and denying My Messenger'

إِنَّآ أَرْسَلْنَا عَلَيْهِمْ صَيْحَةً وَحِدَةً فَكَانُواْ كَهَشِيمِ الْمُحْتَظِرِ

(Verily, We sent against them a single Sayhah, and they became like straw Al-Muhtazir.) They all perished and none of them remained. They were no more, they died out, just as plants and grass dry and die out. As-Suddi said that they became like the dry grass in the desert when it becomes burned and the wind scatters it all about. Ibn Zayd said, "The Arabs used to erect fences (Hizar, from which the word, Al-Muhtazir, is derived) made of dried bushes, around their camels and cattle, so Allah said,

كَهَشِيمِ الْمُحْتَظِرِ

(like straw Al-Muhtazir.)