The reported signs were the information that Allah willed about their occurrence in future and were in effect at the time that the Imams (AS) spoke about them. In other words, with their vision in the knowledge of what had been willed to happen, the Imams (AS) mentioned some of the signs that Allah had willed and planed at that time. However, Allah has not promised the occurrence of the planned signs, and thus all such signs are subject to change due to Allah's new decision (al-Badaa)
The traditions state that amongst all the signs there are few sings that are definite, which means it is unlikely that Allah changes His will on their occurrence. Thus, they are very likely to take place before the advent of Imam al-Mahdi (AS). Umar Ibn Hanzala narrated: Imam al-Sadiq (AS) said, "There are five definite signs before the rising of al-Qa'im, which are:
(the rising of) al-Yamani and al-Sufyani, the (heavenly) cry/call (by Gabriel which will be heard all over the world), the murder of Nafs al-Zakiyya, and the sink (of the Sufyani army) into (the land of) al-Baydaa (located between Mecca and Medina)."
Even for such definite signs Allah reserves al-Badaa. Al-Badaa is the origination of a new plan by Allah. Allah may change those of the definite wills that are not categorized as His Sunan or His promises. For instance, Allah informed us through His Apostle (peace be upon him and his household) that before the reappearance of Imam al-Mahdi (AS), al-Sufyani would certainly rise. This is a definite will, but it is not categorized as a promise. It is just an insisted future event meaning that it is unlikely that Allah cancels His permission for the occurrence of this event, though it is still possible. According to the following tradition, Allah may make Badaa even in such insisted news. Dawud Ibn al-Qasim al-Ja'fari narrated:
We were with Imam al-Jawad (AS) when the issue of Sufyani was brought up and the traditions which state that his advent is of the definite matters. I said to Imam al-Jawad (AS), "Does Allah make Badaa in the definite matters?" He (AS) replied, "Yes." I said, "Then, we have a fear that Allah makes Badaa in (the rising of) al-Qa'im." The Imam replied, "al-Qa'im is of the promises, and Allah does not break His promises (referring to verses 3:9 and 13:31)."
In other words, Allah will not fail in any of His promises including the annihilation of injustice and the establishment of the government of justice on the earth by Imam al-Mahdi (AS).
This was Allah's testimony in verses of Quran that we quoted in previous section. However, Allah may make Badaa on the time of reappearance of Imam al-Mahdi (AS) and may advance or postpone it. Moreover, He may cancel the occurrence of the definite signs that were supposed to take place before the Imam's (AS) advent, as the above tradition explained. The question that may arise here is that what the significance of canceling a sign by Allah is. To answer this, let us first discuss the notion of al-Badaa in next article. This is one of the complex issues that has confused many people's minds, and consequently the enemies of the Ahl al-Bayt (peace be upon them) have taken the advantage of this confusion to attack our faith.
* Source: alhassanain.com