For a long time after Hazrat Mahdi (as) begins work after his appearance in the early Hijri 1400s, only a very few people will know that he is Hazrat Mahdi (as). Our Prophet (saas) received the prophethood at the age of 40, but very few people knew that he was a prophet at that time. The same thing applies to many prophets.
Bediuzzaman Said Nursi also says that Hazrat Mahdi (as) will not be recognized when he first appears. He says that initially even Hazrat Mahdi (as) himself will be unaware that he is the Mahdi of the End Times. In this passage, he says that only a very few believers of deep faith can recognize the Prophet Jesus (as), Hazrat Mahdi (as) and the antichrist, whom he refers to as the personages of the End Times.
However, as we said, this world is the arena of trial. The door is opened to the reason, but the will is not taken from the hand. SO, WHEN THOSE INDIVIDUALS, and even the terrible antichrist, APPEAR, MANY PEOPLE AND EVEN HIMSELF WILL NOT KNOW TO START WITH THAT HE IS THE ANTICHRIST. THOSE INDIVIDUALS OF THE END OF TIME WILL BE KNOWN THROUGH THE INSIGHT AND THE LIGHT OF BELIEF. (Bediuzzaman Said Nursi, Words / Twenty-Fourth Word - Third Branch, p. 355)
The great scholar and mujaddid Sayyid Muhammad ibn Rasul al-Hussein al-Barzanji of Medina makes the following statement in his expanded work “Al-Isha'at ul Ishraat us Saa'at” (Portents of the Judgment Day), referring to Al-Qawl al-Mukhtasar by Ibn Hajar al-Haythami: “ALL THESE TRADITIONS ARE TRUE IN TERMS OF THEIR OCCURRENCE AND SOUNDNESS.” In other words, ALL THE DIFFERENT TIMINGS SET OUT IN THE HADITHS ARE TRUE, AND THESE TIMINGS REFER TO DIFFERENT PERIODS IN THE LIFE OF HAZRAT MAHDI (AS), WHO, BY ALLAH’S LEAVE, WILL HAVE A LONG LIFE, as reported by the Prophet (saas).
Hazrat Mahdi (as) will possess certain characteristics of earlier prophets. Among these is his being long-lived, LIKE THE PROPHET ADAM (AS) AND THE PROPHET NOAH (AS).”(Bihar al-Anwar, Vol. 51, Ansariyan Publications, collected by: Muhammad Baqr al-Majlisi, Iran-Qum, 2003, p. 217)
The following account is the statement on pages 185 and 186 of the Turkish edition of Sayyid al-Barzanji’s Portents of the Judgment Day and notes the different periods of service during Hazrat Mahdi’s (as) tenure:
Muhammad ibn Rasul al-Hussein al-Barzanji makes the following important statements:
First, the Prophet (saas) says much about his community, the Ahl al-Bayt. He has described how they will be rescued from all kinds of oppression and persecution. This is dependent on a justice that will be applied over a long period. Short times such as seven or nine years are insufficient.
Second, just like Dhu’l Qarnayn (as) and Solomon (as), Hazrat Mahdi (as) will rule the whole world. He will establish mosques and buildings in other countries, and a short time such as nine years will be inadequate for his intellectual struggle and other activities.
Third, life spans will be extended in his time. THE PROLONGATION OF LIFE SPANS MEANS THAT HE WILL ALSO BE LONG-LIVED... Otherwise, the extension of life spans would be meaningless.
Fourth, he will make a four-year peace treaty with the people of Rum. Under that he will live in Constantinople for seven years. His going to and leaving there twice will of course take years. The same applies to his intellectual struggle against the Sufyan. Because as described above, the Sufyan will abrogate the treaty three years after swearing allegiance to him, after which he will have to struggle him on the level of ideas.
His spiritual conquest of India and other countries will naturally take many years. What I have described is also found in various traditions.
All these things show that the period of his sovereignty will last longer than nine years. That being the case, SEVEN YEARS ARE TOTALLY RESTRICTED TO HIS FULL RULE OVER ALL COUNTRIES, AND NINETEEN YEARS TO HIS INTELLECTUAL STRUGGLE AGAINST THE SUFYAN, HIS INTELLECTUAL DEFEAT OF HIM, HIS [SPIRITUAL AND INTELLECTUAL] CONQUEST OF COUNTRIES AND ALL PEOPLE COMING UNDER HIS COMMAND... (in other words, the time involved in this is a period of nineteen years...)
I have stated above: He will make nine years of peace with the Rum, his intellectual struggle against and victory over them will take approximately ten years. His entry into Sham, the Sufyan swearing allegiance to him, and then retracting that allegiance three years later, and his thus embarking on an intellectual struggle against him and the passage of a number of years thereafter will take up a total of twenty-four years... His entry into Mecca, his demolition of the intellectual system of the Amr of Mecca, and therefore HIS SPIRITUAL AND INTELLECTUAL CONQUEST OF ALL THE COUNTRIES OF THE HEJAZ WILL TAKE SOME FORTY YEARS... Then, his spiritual and intellectual conquest of all countries and the appearance of Hasheem of Khorasan will take no little time! ... It is likely that he will then rule for nine years or less following the descent of the Prophet Jesus (as)... (Al-Barzanji, Al-Isha'ah li-ashrat al-sa'ah, pp. 185-186)
As we have seen, the great Islamic scholar Muhammad Ibn Rasul al-Hussain al-Barzanji describes various periods during Hazrat Mahdi’s (as) time of service and says it will take this great mujaddid some 40 years to cause the moral values and virtues of the Qur’an and the Sunnah of the Prophet (saas) to rule the world. During that time, Hazrat Mahdi (as) will be occupied with plots and conspiracies against him, and imprisonment, and there will be a period of ghaybah (absence, concealment). In addition, the hadiths say he will have a group of 313 followers, and he will sincerely work to bring them together and strengthen their faith. Hazrat Mahdi (as) will also go through a period of imprisonment, after which he will put an end to the captivity of Muslims and eliminate all the pain, suffering and oppression they face. He will also strive to establish the Qur’anic moral values among people and to set up the Turkish-Islamic Union. However, none of these activities will be completed in as short a time as 7 or 10 years, and each one will take a very long time.
Hazrat Mahdi (as) will also engage in construction work in countries across the world and erect buildings and masjids where Muslims can worship freely. However, this work will be accomplished over a much longer period of time than 9 years. On the other hand, he will be engaged in an intellectual struggle against the system of the Sufyan, and his spiritual campaign against the hypocrites who make that system up will last for many years. In fact, it will take the next 24 years. It will also take him a very long time to achieve the spiritual conquest of the countries of the world, in other words, to bring about the acceptance of the moral values and virtues of the Qur’an and the Sunnah of our Prophet (saas). Al-Barzanji says that Hazrat Mahdi (as) will strive for 40 years to bring about the global dominion of Islamic moral values as a result of these activities. This is significant evidence that Hazrat Mahdi (as) will certainly not be recognized the moment he appears in Hijri 1400 and that all these activites listed above will take a very long time, at least 40 years; in other words, 40, 50 or 60 years.