And of Keturah, whom he took after Sarah's departure, we read, "Then again Abraham took a wife, whose name was Keturah."  Lo! both are called wives, yet both are found to have been concubines; for the Scripture afterward says, "And Abraham gave his whole estate unto Isaac his son. But unto the sons of his concubines Abraham gave gifts, and sent them away from his son Isaac, (while he yet lived,) eastward, unto the east country."  Therefore the sons of the concubines, that is, the heretics and the carnal Jews, have some gifts, but do not attain the promised kingdom; "For they which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed, of whom it was said, In Isaac shall thy seed be called."  For I do not see why Keturah, who was married after the wife's death, should be called a concubine, except on account of this mystery. But if any one is unwilling to put such meanings on these things, he need not calumniate Abraham. For what if even this was provided against the heretics who were to be the opponents of second marriages, so that it might be shown that it was no sin in the case of the father of many nations himself, when, after his wife's death, he married again? And Abraham died when he was 175 years old, so that he left his son Isaac seventy-five years old, having begotten him when 100 years old.