http://en.wikipedia.org/wiki/Khazars
The Khazars enjoyed close relations with the Jews of the Levant and Persia. The Persian Jews, for example, hoped that the Khazars might succeed in conquering the Caliphate.[12] The high esteem in which the Khazars were held among the Jews of the Orient may be seen in the application to them, in an Arabic commentary on Isaiah ascribed by some to Saadia Gaon, and by others to Benjamin Nahawandi, of Isaiah 48:14: "The Lord hath loved him." "This," says the commentary, "refers to the Khazars, who will go and destroy Babel" (i.e., Babylonia), a name used to designate the country of the Arabs.[13]