How did Muhammad's message change Arabia?

Answer 1

First Muhammad (PPNH) is a messenger of Allah (the only God that exist), So Muhammad's message (PPNH) is essentially the existence of one God, all-powerful but also merciful, and he freely acknowledges that other prophets - in particular Abraham, Moses and Jesus - have preached the same truth in the past.

Secondly the Arabians who lived in the Peninsula were idiots they really had very bad cultures; they used to kill girls leave boys when they were born, they used to worship food, stones and alot others. Meanwhile there is Allah whom the worship is for him only, So he sent his messenger Muhammad (PPNH) to declare them the right path and Allah has helped his messenger as Allah typically did to the previous messenger and then a light shone in the Peninsula and later reached all over the world.