At this point...
At this point, a large contingent of forces will be sent to attack the Imam (by al-Sufyani), however when this army will reach the place known as Bayda` a location between Makkah and Madinah they will be swallowed into the Earth. In addition, before the advent of the Imam (ajtf), many uprisings will take place such as the revolts of al-Hasani and al-Yamani and according to some traditions, the uprising of al-Yamani is also one of the definite signs.
The hearing of two cries one from the sky and the other from within the Earth is also one of the definite signs. During the first call, Jibra`il will call the name of Imam al-Qa`im (ajtf) and his father and will proclaim that the truth is with ‘Ali ibn. Abi Talib (as) and his Shi’a (followers). Everyone will hear this call in their own language and even the women who are in their house behind locked doors will hear the call.
As well, before the advent of the Imam, a noble person will be killed during the Hajj rites in Makkah. In the traditions, this person has been referred to as the Pure Soul or an-Nafs al-Zakiyyah. Detailed information about this individual has been mentioned in the books concerning the occultation of Imam al-Zaman (ajtf).
The importance of knowing the signs which will take place before the advent of our Imam, especially the definite signs that must occur, can best be understood when we review the history of Islam. We see that some other signs may have already taken place and thus, a number of people falsely claimed to be the Mahdi (ajtf) Without doubt, these people have fallen out of the fold of Islam and it is they who are misguided and are left alone in utter spiritual darkness.
The reason for them falling into this state is that they were not acquainted with the signs related to the advent and uprising of the Imam such that they could follow them. In addition, they lacked awareness of the specific signs which will herald in the advent of the Imam. If they had knowledge of these signs, then they would not have been led astray and would have stayed firm on the Imamate and Wilayat of the Imam (as).
They would not have been fooled nor would they have mistaken anyone else for the real Mahdi (ajtf). Possessing a ma’rifah of the signs of the advent, especially the definite signs which must take place, helps us in differentiating between truth and falsehood, and by recognizing Imam al-Zaman (ajtf), we would actually look forward to and prepare the groundwork for his uprising.