Prophet Hud - 11:61
"And to Thamud sent their brother Salih. He said: "O my people, serve Allah, there is no god but Him. It is He who brought you out of the earth and created you and settled you therein. So seek forgiveness from Him and then turn to Him. Surely my Lord is Near, the Answerer."
The crimes of the people of Thamud that they should ask forgiveness:
Prophet Hud/11:62
"They said: "O Salih, before this you were a popular source of hope among us. Do you now forbid us from what our forefathers used to serve? We are in doubt about what you call us to."
The Poets/26:141
The people of Thamud also denied the messengers.
The Poets/26:151
Do not follow the command of the transgressors.
The Poets/26:152
They do evil in the earth, not good.
The Ants/27:45
"We sent to Thamud their brother Salih to say to them, "Serve Allah."Thereupon they divided into two groups disputing."
The Ants/27:46
"My people,"he said, "why do you hasten to do evil instead of good? Should you not ask forgiveness from Allah that you may be shown mercy?"
The Ants/27:47
"They said, "You and those with you have jinxed us."He said, "Your bad luck is from Allah. Surely you are a people who are put to a test."
The Ants/27:48
There was a gang of nine in the city; they were making mischief in the region and never did anything good.
The Ants/27:49
"They swore by Allah and said to one another, "Let us make a night raid on him and his family and then tell his tribe that we know nothing about their death and that we speak the truth."
The Ants/27:50
So they devised a plan, but We devised a plan before they realized it.