" Not one but two great nations were to look back to Abraham as their father - two great nations, that is, two guided powers, two instruments to work the Will of Heaven, for God does not promise as a blessing that which is profane, nor is there any greatness before God except greatness in the Spirit. Abraham was thus the fountain-head of two spiritual streams which must not flow together, but each in its own course; and he entrusted Hagar and Ishmael to the blessing of God and the care of His Angels in the certainty that all would be well with them.
Two spiritual streams, two religions, two worlds for God; two circles, therefore two centres. A place is never holy through the choice of man, but because it has been chosen in Heaven. There were two holy centres within the orbit of Abraham: one of these was at hand, the other perhaps he did not get know; and it was to the other that Hagar and Ishmael were guided, in a barren valley of Arabia, some forty camel days south of Canaan. "
― , Muhammad: His Life Based on the Earliest Sources