Muhammad PBUh is a prophet, He received revelations from the Almighty Allah which became the first source of laws in Islam. Also, He PBUH was inspired in all His sayings & actions which are called Al-Sunnah & it's the second source of Islamic laws.
So, the background that the prophet Muhammad PBUH had relied on was those revelations plus Allah's inspiration & guidance to Him.
The background for the Muslims to rely on in each of the life details are:
1. The Holy Quran.
2. The Sunnah.
For more clarification, please refer to the related question below & its related questions.
Allah save prophet Muhammad by spider net.
Khadija, prophet Muhammad first wife, was the first who recognized Muhammad as a prophet (BPUH).
Yes, Ahmadis believe in Prophet Muhammad as the final prophet in Islam.
Prophet Muhammad i think
The prophet Muhammad didn't change his name
Prophet MUhammad (PBUH) is the last messenger of Allah.
He was born in Makkah, in the tribe of Quraish.
There has never been a prophet Muhammad war.
Prophet Muhammad.
Muhammad was the last prophet from God.
Prophet Muhammad.
Muhammad was called the final prophet because according to Muslim theology after him there was no prophet to come.