Before the Prophet Muhammad came with his message, prejudice was the law that the Arabs followed. There were a few wealthy Arab men that were the ruling superiors. Everyone else was inferior. Especially discriminated against were black people. The Prophet proclaimed that Islam was the new religion for all humanity, a religion that declared all people as equals: men and women, BLACK and WHITE, etc. Racial discrimination is simply not tolerated under Islamic law.
Equality for All
The superior, arrogant Arabs were offending by this “equality-for-all” ruling. They were willing to die fighting Islam, the religion that threatened their hierarchy. They hoped that Islam would be a passing fad and that racial discrimination would remain common practice in the desert.
Islam did in fact spread throughout Arabia and racial discrimination was abolished.
All mankind is equal
Islam teaches that all mankind is equal, excelling each other only with good deeds. Race does not give anyone an advantage in the eyes of God. Whereas if you racially discriminate against someone, you are disadvantaged; because you are assuming superiority to someone and that is the grievous offense that is arrogance.
The stated in his last sermon, “All mankind is from Adam and Eve, an Arab has no superiority over a non-Arab nor a non-Arab has any superiority over an Arab; also a white has no superiority over black nor a black has any superiority over white except by piety and good action.” The Prophet urged all his followers to strive for piety, justice, and social, gender and RACIAL equality.
Appointment of Bilal to the high position of the muezzin
Furthermore, the Prophet Muhammad appointed Bilal to the high position of the muezzin. A muezzin would call the people to prayer, and Bilal was chosen on account of his fine voice. Bilal was one of the earlier converts to Islam who was beaten terribly by his master for doing such. Abu Bakr, a companion of the Prophet, felt terrible for the way Bilal was being treated and liberated him. Freeing a slave and granting him a prominent position would be deemed absurd in the very bias Pre-Islamic Arabia. But that was the religion of Islam, at work, abolishing racial discrimination.