Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XXXIII

Chapter XXXIII.—Abraham:  His Posterity.

“Therefore Abraham, when he was desirous to learn the causes of things, and was intently pondering upon what had been told him, the true Prophet appeared to him, who alone knows the hearts and purpose of men, and disclosed to him all things which he desired.  He taught him the knowledge of the Divinity; intimated the origin of the world, and likewise its end; showed him the immortality of the soul, and the manner of life which was pleasing to God; declared also the resurrection of the dead, the future judgment, the reward of the good, the punishment of the evil,—all to be regulated by righteous judgment:  and having given him all this information plainly and sufficiently, He departed again to the invisible abodes.  But while Abraham was still in ignorance, as we said to you before, two sons were born to him, of whom the one was called Ismael, and the other Heliesdros.  From the one are descended the barbarous nations, from the other the people of the Persians, some of whom have adopted the manner of living and the institutions of their neighbours, the Brachmans.  Others settled in Arabia, of whose posterity some also have spread into Egypt.  From them some of the Indians and of the Egyptians have learned to be circumcised, and to be of purer observance than others, although in process of time most of them have turned to impiety what was the proof and sign of purity.”