Genesis 17:25

“And Ishmael his son [was] thirteen years old when he was circumcised in the flesh of his foreskin.]. Hence the Arabians, as Josephus f1100 relates, circumcise their children when at thirteen years of age, because Ishmael, the founder of their nation, was circumcised at that age; and Origen f1101 asserts the same; and with which agrees what an Arabic writer says f1102 of the Arabians before Mahomet, that they used to circumcise at a certain age, between the tenth and fifteenth years of their age. So Rauwolff says f1103, there are some, chiefly among the Arabians, that imitate their patriarch Ishmael. As for the Mahometans, though they circumcise, they do not always do it in the thirteenth…”

“- The Sealing of the Covenant 1. שׁדי shaday, Shaddai, “Irresistible, able to destroy, and by inference to make, Almighty.” שׁדד shādad “be strong, destroy.” This name is found six times in Genesis, and thirty-one times in Job. 5. אברהם 'abrâhām, Abraham, from אברם 'abrām “high-father,” and הם hām the radical part of המין hāmôn a “multitude,” is obtained by a euphonic abbreviation אברהם 'abrâhām, “father of a multitude.” The root רהם rhm is a variation of רום rvm; affording, however, a link of connection in sound and sense with the root המה hāmâh “hum, be tumultuous,” from which comes המון hāmôn a “multitude.” The confluence of the biliterals רם rm and הם hm yields the…”