Surah 7. Al-A'raf, Ayah 75

The contents of his message (lit., "that with which he has been sent") appeared to them justification enough to accept it on its merits, without the need of any esoteric "proof" of Salih's mission. In a subtle way, this statement of faith has a meaning which goes far beyond the story of the Thamud. It is an invitation to the sceptic who is unable to believe in the divine origin of a religious message, to judge it on its intrinsic merits and not to make his acceptance dependent on extraneous, and objectively impossible, proofs of its origin: for only through the contents of a message can its truth and validity be established.

As usually happens in such cases, the Believers were the lowly and the humble, and the oppressors were the arrogant, who in selfishly keeping back nature's gifts (which are Allah's gifts) from the people, were deaf to the dictates of justice and kindness. Salih took the side of the unprivileged, and was therefore himself attacked.

Notice the relation between the question and the answer. The godless chiefs wanted to discredit Salih, and put a personal question, as much as to say, "Is he not a liar?" The Believers took back the issue to the higher plane, as much as to say. "We know he is a man of Allah, but look at the justice for which he is making a stand: to resist it is to resist Allah". The answer of the godless was to reject Allah in words, and in action to commit a further act of cruelty and injustice in ham-stringing and killing the she-camel, at the same time hurling defiance at Salih and his God.