God's Management of History
The particular purpose for which God had sent the Prophet Muhammad, may peace be upon him, was to convey the message and guidance he received from God. It was the Prophet’s primary mission. If the Prophet had not undertaken this task, it would have meant that he had failed in discharging his divine duties. Moreover, that being so, his prophethood would have come under the shadow of a doubt. In other words, the prophethood of the Prophet Muhammad, may peace be upon him, could only stand proven in the eyes of God after he had completed the dawah mission. Moreover, by not completing the dawah mission, he would have failed to establish his real role and actual position.
After the end of the prophethood, the followers of the Prophet—the entire Muslim ummah—must assume the mantle of prophethood. They have to carry out the same task that the Prophet carried out in his lifetime. The very basis of their being called the followers of the Prophet is their performing dawah work on his behalf and their continuing to convey the valid message of the divine religion in its original form. If they failed to perform this mission, the words of the above verse of the Quran would become true, as it could have become true for the Prophet on the non-performance of dawah work. In the eyes of God, they would lose the true position of being called the followers of the Prophet Muhammad; may peace be upon him.