Allāh deputed prophets and distinguished them with His revelation. He made them as pleas for Him among His creation, so that there should not remain any excuse for people. He invited people to the right path through a truthful tongue. You should know that Allāh fully knows creation. Not that He was not aware of what they concealed from among their hidden secrets and inner feelings, but in order to try them as to “..which of them performs the best deeds” (18:7), so that there is reward in respect of good acts and chastisement in respect of evil acts.
[The position of Ahlu’l-bayt (the Household of the Holy Prophet) :] Where are those who falsely and unjustly claimed that they are deeply versed in knowledge, as against us, although Allāh raised us in position and kept them down, bestowed upon us knowledged but deprived them, and entered us (in the fortress of knowledge) but kept them out. With us guidance is to be sought and blindness (of misguidance) is to be changed into brightness. Surely Imams (divine leaders) will be from the Quraysh. They have been planted in this line through Hāshim. It would not suit others nor would others be suitable as heads of affairs
[A part of the same sermon about those who are against the Ahlu’l-bayt :] They have adopted this world and abandoned the next world; left clean water and drunk stinking water. I can almost see their wicked one  who committed unlawful acts, associated himself with them, befriended them and accorded with them till his hair grew grey and his nature acquired their tinge. He proceeded onward emitting foam like a torrential stream not caring whom he drowned, or, like fire in straw, without realizing what he burnt.
Where are the minds which seek light from the lamps of guidance, and the eyes which look at minarets of piety? Where are the hearts dedicated to Allāh, and devoted to the obedience of Allāh? They are all crowding towards worldly vanities and quarrelling over unlawful issues. The ensigns of Paradise and Hell have been raised for them but they have turned their faces away from Paradise and proceeded to Hell by dint of their performances. Allāh called them but they showed dislike and ran away. When Satan called them they responded and proceeded (towards him).
 Here the reference is to ‘Abd al-Mālik ibn Marwān who committed extreme atrocities through his officer al-Ḥ ajjāj ibn Yūsuf ath-Thaqafi.