They will oppose him since they did not believe in his sayings and practices...

They will oppose him since they did not believe in his sayings and practices, as it does not match with their innovations and the innovations of their ancestors. We do not know of anything brighter than sunshine, which could be sensed by our faculties. The reappearance Imam Mahdi (AS) will be clearer than that, and no one would remain ignorant about Imam al-Mahdi (AS) when he starts his mission.

However, no one would be able to believe in him if he denied/disbelieved him (his existence, his rights, or his Sunna) before the time of his reappearance; or, it is better say, believing in him at that time would be of no use for a disbeliever. It is just like believing in Allah on the Day of Judgment, which will be of no benefit for the disbelievers. Those who remain doubtful about his existence during the time of occultation will have no way to escape from his sword once they meet him (AS).

Allah stated in Quran: "... On the day that certain signs of thy Lord do come, no one would benefit from believing in (that sign) if he did not believe (in that) before, or such belief is no good for him. Say, 'Wait! We too are waiting/expecting'. (6:158)" Ibn Ri'ab narrated that on the commentary of the above verse, Imam Ja'far al-Sadiq (AS) said: "The 'Signs' are the Imams (AS), and the 'expected sign' is al-Qa'im (AS).

On that day, no one would benefit from believing in (that sign) if he did not believe in him before his rising by sword even if such person believed in (the Imamat of) his ancestors, peace be upon them."[^23] The bad news, however, is that most of those who believe in Imam al-Mahdi (AS) will doubt his existence over time due to the length of the time of occultation and because of various types of afflictions that befall people during this period.

Therefore, when the Imam (AS) starts his mission, the believers will be very few in number. Saqr Ibn Dilf narrated: I asked Imam al-Jawad (AS) why Imam al-Mahdi (AS) is called al-Qa'im. He (AS) wept and replied, "Because he will rise after his remembrance is dead (in the society) and when most of the believers in his Imamat have turned back (from their belief)." I asked why he is called al-Muntadhar (the awaited).

He (AS) replied, "Because there shall be an occultation for him whose period shall be prolonged. The sincere ones shall wait for him, the doubtful ones shall deny him, the rejecters shall ridicule his remembrance, and the proposers of time (for his reappearance) shall increase.