It must be noted that Muhammad was born into a pagan-worshipping tribe, the Quraysh, whose god, "Hubal," ranked highest among 360 other deities that were worshipped throughout the Arabian region. The pre-Islamic custom, prior to Allah being declared the only deity, was for all tribes to make an annual pilgrimage to worship their gods in the Ka'ba shrine in Mecca.*

 

Being an orphaned youth, Muhammad was raised for a short period by his grandfather and was taught the customs of his tribe. It is believed that, as a youngster, Muhammad had also participated in pagan worship at the Ka'ba.

 

As mentioned in the topical section: An "Angelic Revelation:" Birth of Islam,

Muhammad was forty years old when he proclaimed his revelation that  "Allah," was the only true god.

 

Muhammad's  revelations included a mixture of Jewish and Christian teachings along with many of the rituals and traditions of his own tribe, the Quraysh, who soon turned against him for introducing a new religion.

 

Convinced that he had been contacted by God through the archangel, Gabriel, Muhammad set out to cleanse the world of all pagan idolatry and to establish a one world religion in an attempt to supersede all others. Upon gaining power, Muhammad ordered all pagan idols within the Ka'ba to be destroyed, including Hubal, the deity of the Quraysh, who was believed to be the "moon god." His proclamation was that this battle would continue until belief in the god, Allah, prevailed everywhere. (Qur'an: 002.193 / 008.039)

 

* References: