In a letter to Ash’ath Ibn Qais, Imam Ali (AS) wrote:

Indeed, management and governance for you is not a tool to attain water and bread (wealth), rather it is a trust around your neck. You must obey your commander and Imam. You have no right to oppress people and act on an important task without a command [1]. In another letter to some officials, Imam Ali (AS) wrote: Whoever considers responsibility as unimportant and betrays it, and does not cleanse his body and religion from betrayal, has opened doors of indignity on himself, and will be humiliated on the Day of Judgement. Certainly, betraying Ummah, is the biggest/worst betrayal, and deception by leaders is the most indecent of deceptions [2]. Imam Ali (AS) also told Ibn Abbas: Swear to God, for me these old shoes are more precious than rule over you, unless I can prevent injustice. And if there was no covenant between God and scholars to stand up against oppression and hunger of the oppressed ones, I would have thrown the bridle of the camel of Caliphate on its hump [3].

[1] Nahjul Balaghah, Letter 5.

[2] As Above, Letter 26.

[3] As Above, Sermon 3.

Source: en.shafaqna.com