Is there a single Messiah or many teachers for different peoples?
Islam teaches the second. God has sent messengers throughout the ages, each for a particular time and a particular people.
According to the Holy Qur’an, God has never left people on their own. The first two verses above say that no people has been left without a warner and that every people has been given a guide. So God has not spoken only once or in only one place.
Each of these messengers came in his own time and to his own people. They spoke the language of their listeners and answered their questions and needs. Moses (as) came to the Children of Israel, and Jesus (as) too was sent to them. Other peoples had their own messengers, even if not all their names have come down to us.
This is why a Muslim sees in many great teachers of human history possible messengers of God. Their message was at heart the same, because it came from the same God. Differences arose mainly through time, place, and what later generations made of it.
The third verse above adds one more thought. After the many messengers to individual peoples, God sent the Holy Prophet Muhammad (saw) to all of mankind. In this way the many paths of the earlier messengers come together in one message for everyone.