first, there was need for a prophet to be sent unto a certain nation to which no prophet had been sent before and the message brought by the prophet of another nation could not have reached these people.
second, there was need to appoint a prophet because the message of an earlier prophet had been forgotten by the people, or the teachings of the former prophets had been adulterated and hence it had become impossible to follow the message brought by that prophet.
third, the people had not received a complete mandate of allah through a former prophet. hence succeeding prophets were sent to fulfill the task of completing the religion of allah.
fourth, there was need for a second prophet to share the responsibility of office with the first prophet.
it is obvious that none of the above needs remains to be fulfilled after the advent of prophet muhammad (peace and blessings be upon him).
the qur’an says that prophet muhammad (peace and blessings be upon him) has been sent as a bearer of instructions for the whole mankind. the cultural history of the world bears testimony to the fact that since the advent of the prophet (peace and blessings be upon him) up to the present time, such conditions have always prevailed in the world which were conducive to transmitting his message to all nations at all times. it follows, therefore, that different nations no longer need different prophets after the time of the prophet (peace and blessings be upon him). the qur’an and the records of hadith and the biographical details of the life of muhammad (peace and blessings be upon him) stand witness to the fact that the divine message brought into this world by the prophet is extant in its original and pure form. the prophet’s message has suffered no process of distortion or falsification. not a single word has been added to or expunged from the book which the prophet (peace and blessings be upon him) brought unto the world from almighty allah, nor can anyone make additions to or delete anything from it till the day of resurrection.
the message which the prophet (peace and blessings be upon him) conveyed by word and action has been transmitted to us in such comprehensive, pure, and original form that we feel as if we were living in the environment and period of the prophet (peace and blessings be upon him).
in this way the second condition under which prophets are sent unto the world has also been fulfilled.
third, the qur’an clearly affirms that allah has finally completed his divine mission through the agency of prophet muhammad (peace and blessings be upon him). hence there is no room for a new prophet to carry the divine mission to completion.
as regards the fourth condition, if a partner were really needed, he would have been appointed in the time of prophet muhammad (peace and blessings be upon him) to share the burden of his ministry. since no co-prophet was appointed, this condition also stands fulfilled.
we should, therefore, look around for a fifth condition under which a new prophet might be needed after muhammad (peace and blessings be upon him). if a man argues that people have fallen into depravity, hence there is need for a new prophet to reform the degenerate people, we shall ask him, when did a prophet ever come to introduce reforms only that we should need one now to carry out the work of reformation? a prophet is appointed so that he may be the recipient of divine revelation, and divine revelations are made with express purpose of transmitting a new message or to correct the wrongs that have crept into an earlier religion.
when the qur’an and the sunnah of the prophet (peace and blessings be upon him) have been preserved in their original and comprehensive form and when the divine mission has been completed by muhammad (peace and blessings be upon him), all possible need for the transmission of divine revelations have now been fulfilled and there is further need only of reformers to cleanse the evils of mankind, but there is no room for the prophets.