Prophet Hud - 11:84
"And to Median We sent their brother Shu´ayb. He said: "O my people, serve Allah, you have no god but Him. Do not keep the measure and the weighing deficient. I see you in prosperity and I fear for you the torment of an encompassing Day."
Why does Allah choose messengers from among His people?
Prophet Abraham/14:4
We send every messenger only in the language of his people so that he may make them aware. Allah leads astray whom He wills and guides whom He wills. He is Mighty, Wise.
The Poets/26:198
Had We sent it down to some foreigners,
The Poets/26:199
And if he had recited it to them, they would not have believed in it.