@ Shai
Naib does not means assistant. Naib is every human being on earth, for fulfilling the commands of Allah.
If an Imam (leader) or Amir (ruler) becomes corrupt he should first be given a call to Islam (submission) in private, or possibly in public if his evil deeds were done in public. If he does not turn away from his evil deeds, he should be overthrown or removed from position. However, in the process of removing him from position, he should not be physically fought, such as waging war with weapons. This is because the ruler is still Muslim, and the Muslims are not to attack or kill another Muslim. If, however, the Muslim leader or ruler completely abandons his salat, he nullifies his Islam and can be fought if necessary.
Many Muslim scholars have commented on when it is permissible to disobey or remove the Khalifa, which is normally forbidden when the Khalifa is meeting all his responsibilities under Islam.
- Al-Mawardi believed that if the Khalifa has followed the Qur'an and Sunnah, the people must follow and support him. On the other hand, if he becomes either unjust or handicapped to the point of ineffectiveness (such as blindness or an amputation), then he must be removed.
- Al-Baghdadi believed that if the Khalifa deviates from justice, the ummah needs to warn him first to return to the straight path. If this fails, then he can be removed.
- Al-Juwayni held that since Islam is the goal of the ummah, any Khalifa who steps away from this goal must be removed.
- Ashighistani wrote that if the Khalifa is found to be ignorant, oppressive, indifferent, or a kafir after his selection, then he must be removed.
- Al-Ghazali believed that an oppressive Khalifa must be told to desist from his crimes. If he does not, then he must be removed.
- Al-Iji believed the ummah has a definite list of permissible reasons to remove the Khalifa.
- Al-Asqalani wrote that if the Khalifa starts to act as an unbeliever, it is prohibited to obey him and obligatory to fight him. It is obligatory to stand against him if one can - and this entails a big reward. Those people who choose to ignore the situation are in sin, whereas those who cannot fight should emigrate (to organize resistance). Al-Asqalani used two ayahs from the Qur'an in particular to support his position. The first is from Surat Al-Ahzab 67-68, "...And they would say, 'Our Lord! We obeyed our chiefs and our great ones, and they deceived us as to the right path. Our Lord! Give them a double penalty and curse them with a very great curse'...", and the second is from Surat Al-Baqara 167, "...And those who followed would say, 'If only we had one more chance, we would clear ourselves of them, as they have cleared themselves of us.' Thus will Allah show them (the fruits of) their deeds as (nothing but) regrets. Nor will there be a way for them out of the Fire..."
- Muslim reported that Ibn Umar said the Prophet ordered every Muslim to obey their leader unless commanded to do something bad, in which case they must neither obey nor listen. Muslim also reported that Ibn Malik said the best leader is the one where mutual love exists between him and the people, and the worst leader generates mutual hate. However, even in the latter case, fighting the Khalifa (with weapons) is prohibited unless he enters kufr by stopping prayers or zakat for example.
- Abu Daud reports from Ibn Ujrah that the Prophet entered a masjid, and said there will come leaders after him who disobey the Qur'an and Allah. Those who help them are not of the Muslims, but if someone opposes them, he or she is of the Prophet's people.
I dont agree with those who say that we have chosen them so why should we complain now. Yes, people choose them because people put there trust in them and it's the ruler duty to come up to their expectations. If he does not, masses have all the right to raise their voice against him and get him removed in a proper way.
@ All
Please do not compare the corrupt leaders with previous Imams and Khulafa e Rashideen.