The last and final prophet that the One True God sent to humanity was the Prophet Muhammad. Muhammad explained, interpreted and lived the teachings of Islaam the same as all the previous Prophets. Even though other religious communities claimed to believe in One God, over time they had corrupted their beliefs by taking their prophets and saints as intercessors with Almighty God. Some religions believe their prophets to be manifestations of God, ʺGod Incarnateʺ or the ʺSon of Godʺ. All of these false ideas lead to the creation being worshipped instead of the Creator, which contributed to the idolatrous practice of believing that Almighty God can be approached through intermediaries. In order to guard against these falsehoods, the Prophet Muhammad always emphasised that he was only a human‐being tasked with the preaching of Godʹs message. He taught Muslims to refer to him as ʺthe Messenger of God and His Slaveʺ. To Muslims, Muhammad is the supreme example for all people ‐ he was the exemplary prophet, true worshipper, mil‐itary leader, ruler, teacher, neighbour, husband, father and friend. Unlike other prophets and messengers, the Prophet Muhammad lived in the full light of history. Muslims donʹt need to have mere ʺfaithʺ that he existed and that his teachings are preserved ‐ they know it to be a fact! Even when his followers only numbered a few dozen, Almighty God informed Muhammad that he had been sent as a mercy, to all of mankind. Because people had distorted or forgotten Godʹs messages, God took it upon Himself to protect the message revealed to Muhammad. This was because Almighty God promised not to send another messenger after him. Since all of Godʹs messengers have preached the message of Islaam ‐ i.e. submission to the will of God and the worship of God alone ‐ Muhammad is actually the last prophet of Islaam, not the first!
Source: http://www.islaam.ca/, the free Dawah leaflet, 7 Fundamental Questions on Islaam, Question 4.