What is the authenticity of the hadith: "The Imams are from Quraish; they have a right over you, and you have a right over them just as much: if they are asked for mercy, they show mercy; if they make a covenant, they fulfill it; and if they rule, they rule justly. Whoever among them does not do that, upon him be the curse of Allah, the angels, and all mankind"? And does its ruling apply today with the intermingling of lineages? And is it permissible to curse unjust rulers based on it?

The Hadith is authentic, narrated by Ahmad, An-Nasa'i, Al-Bayhaqi, and At-Tabarani, from the Hadith of Anas ibn Malik. It was authenticated by Al-Albani, Shu'ayb, and Al-Arna'ut. As for the possibility of this occurring today, yes, it is possible, as lineages have not become entirely mixed, and people still know their ancestry. We have previously explained the evidence for the Imams being from Quraysh. If a competent person from Quraysh cannot be found, their right is forfeited, and the leadership is given to someone else to preserve the public interest.