( فَتَوَلَّىٰ عَنْهُمْ ) (And he turned away from them): The Prophet Salih (PBUH) abandoned them.

( وَقَالَ يَا قَوْمِ) (and said, “O my people): A question raised: ‘How did the Prophet Salih (PBUH) speak to them after they were dead? There is a Hadith in Sahih Al-Bukhari, saying:

“The Prophet (saws) looked at the people of the well (the well in which the bodies of the pagans killed in the Battle of Badr were thrown) and said, “Have you found true what your Lord promised you?” Somebody said to him, “You are addressing dead people.” He replied, “You do not hear better than they but they cannot reply.”[1]

After Prophet Salih (PBUH) abandoned them, he turned around after they had fallen prone to the earthquake and said:

( لَقَدْ أَبْلَغْتُكُمْ رِسَالَةَ رَبِّي وَنَصَحْتُ لَكُمْ ) (I had certainly conveyed to you the message of my Lord and advised you). In this verse, (Message) comes in singular, whereas other Prophets (PBUT) said it in plural (Messages), that is because the Message of Allah (swt) is one consistent message and it includes all the Messages together, thus he said that he had delivered the Message of his Lord (swt) to his people.

This is where the scene of the story of Thamud with their Prophet Salih (PBUH) ends in this Surah. Other scenes are mentioned in other Surahs that mention him (PBUH), the she-camel, and the earthquake. As for the people of Thamud, of whom Allah (swt) said:

 وَكَانُوا يَنْحِتُونَ مِنَ الْجِبَالِ بُيُوتًا آمِنِينَ

(And they used to carve from the mountains, houses, feeling secure.) (Al-Hijr: 82)

  All what they had carved remained after them as a proof of the time they existed and of the cultural and architectural development of their age.

[1] Sahih Al-Bukhari, the Book of Funerals, Hadith No. 1304.