The Heights - 7:73 "And We sent to the people of Thamud their brother Salih: "O My people, worship Allah. You have no god besides Him. A clear proof has come to you from your Lord, and this camel of Allah will be a sign for you. Let him graze on Allah´s land. Do not harm him, lest a painful torment seizes you."
What proof was the camel given to Thamud?
The Sun/91:13 "Allah´s Messenger had said to them: "Do not touch the camel of Allah and its water"."

The Poets/26:155 "He said, "Here is that camel. It has a certain time when it will drink water. And you have a certain day when you will drink water."

The Moon/54:27 We will send the camel as a test. Watch over them, be patient.
The Moon/54:28 Inform them that the water (with the camel) will be shared between them. Each drink will be offered in turn.