If such people are not available it would be necessary to...

If such people are not available it would be necessary to have at least one supporter of an unusual quality who is similar to the Messenger in sincerity courage and strength. Such a person would be expected to be found among the relatives of the man of the message since the relatives are expected to be more sympathetic to him than others.

The Holy Qur'an informs us that when Moses received the Command of God: "Go to Pharaoh certainly he has exceeded the limit “He asked his Lord to strengthen him through a minister from his own family! "He (Moses) said: O my Lord expand my breast. Ease my task for me and remove the impediment from my speech. So they may understand what I say. And give me a minister from my family Aaron my brother. Add to my strength through him and make him share my task." The Holy Quran Chapter 20 verses 25-32.

Muhammad is the final of the prophets. His message is the conclusion of all heavenly messages. His message therefore must succeed and stay forever.God runs the affairs of the world usually according to the law of cause and effect and through natural courses. Therefore He did not order His Messenger Muhammad to face the whole society at once with the invitation to Islam because this might lead to the failure of the mission rather than to its success.

Wanting him to go gradually in his invitation He issued to him a command (after three years from the beginning of his Prophethood) to begin with his close relatives. From the Holy Qur'an: "And warn thy nearest kinsmen. And lower thy wing to the believers who follow thee." The Holy Quran Chapter 26 verses 214-215. When this command came down the Messenger of God invited the descendents of Abdul-Muttalib (they were forty men) to a banquet which contained little amounts of food and milk.

They ate and drank until they became full. Then the Messenger spoke saying: "O children of Abdul-Muttalib by God I do not know any young man from among the Arabs who has ever brought to his people better than I brought to you. I brought to you the goodness of this world and of the Hereafter and God has commanded me to invite you to it.

Who is among you willing to be my minister in this mission and he will be my brother my executor and my successor in you?" None of them responded but ‘Ali who was the youngest among them. He stood up and said: "Messenger of God I will be your minister in this mission." The Prophet repeated his invitation but none responded except ‘Ali who repeated his words.