The Chachnāma (Fatḥnāma-yi Sind) 2.6

2.6

And as his obligations as well as those of his descendants (may they be perpetually exalted and their ancestors absolved) are clinging to my neck, let me bring this book to his notice, since it is a book of conquest, which is based on spiritual rectitude and temporal excellence, and of which learned philosophers and generous kings would be proud, because all men attain advancement to perfection by acknowledging as true the belief of the people of Arabia and professing the faith of the possessors of sound principles,” (I was thus anxious to dedicate) this book of conquest, which treats of the acts of valour and bravery which is by descent and lineage an Arabian family; because in former years the conquest of Khurásán and 'Ajam had been completed by their noble grandfather, the great Amír, the glory of the chief men of Arabia, the administrator of religious affairs, the supporter of mankind, the pride of the children of Kuraish, Abú Músa Ash-hari. There are several books and detailed accounts written about his being the leader of armies and the conductor of forces. Wherever the unbelievers have been defeated and routed, the banners of Islám have been carried by their and his ancestors, as if this was a hereditary monopoly of theirs. This record of their successes goes up to the Commander of the Faithful, 'Umar son of Khattáb (may the great God be pleased with him!), who, in addressing the true believers publicly, used to speak highly of the valuable services of this family.