Muhammad declared him self to be the messenger why ?
The traditional explanation of why Muhammad declared himself to the messenger of God is that he received a revealation from God in which God gave him divine teaching and asked him to spread that teaching in the world.
A more modern interpretation is that Muhamman wanted to strengthen his position in his tribe, the Quraysh tribe. By declaring himself the messenger, he could bring that tribe under his control and use his position to conquer other tribes in Arabia.
A more modern interpretation is that Muhamman wanted to strengthen his position in his tribe, the Quraysh tribe. By declaring himself the messenger, he could bring that tribe under his control and use his position to conquer other tribes in Arabia.