Ambrose of Milan : It was not because he was ablaze with the heat of some unbridled passion, not because he was overcome by the charm of seductive beauty that Abraham gave preference to a relationship with a slave girl over the conjugal bed, but through a desire to procure a posterity and to enlarge his progeny. After the flood the human race was still numerically sparse. Hence it was also a matter of moral obligation that no one be seen to have failed to render the debt to nature. For this reason, even the children of holy Lot were inspired by this motive to procure a posterity for themselves so that the human race would not become extinct. Thus the merit of having done one's duty to society excused individual guilt. And it is not without significance that the wife is presented as the instigator of the deed. In [a] sense [this] exculpates her husband, so that no one could believe that he was carried away by some mad perversion. At the same time … women might learn to love their husbands, not to allow themselves to be tormented by empty suspicions of infidelity and not to dislike their stepchildren, when they themselves have been childless. That wonderful wife desired only that her husband forgive her sterility, and, wishing to avoid being herself the reason for her husband's not having children, she persuades him to go in to the slave girl. Later on, Leah and Rachel did the same thing. Learn, O woman, to put aside jealousy, which often drives women to madness. — On Abraham Didymus the Blind : As we said above, it is a most authentic proof of moderation (sophrosyne) that Sarah gives in offering her slave girl to Abraham without a hint of jealousy, after she had observed that in ten months' time she had not conceived. And we have acknowledged too the passionlessness (apatheia) of the wise man, in that his clear purpose in yielding to his wife's request was to have children.The anagogical [mystical] sense has already been expounded. It is in accordance with its goal that virtue asks us to first make use of the introductory sciences so as to first have children by them. This does not prevent the works of preparatory education from being themselves children of virtue, since they are engaged for the sake of virtue. By employing these, it was not long before the wise man effected a conception, for progress is spontaneous for the wise man. — ON Genesis 236-37 Didymus the Blind : Virtue's purpose was, as we have said, that the wise man do training exercises first in preliminary education and shadow so that later, with this training behind him, he might arrive at greater things—which is the proper procedural order. It is likewise illogical that after the knowledge of perfect things one should turn back to petty things. This is in fact what the apostle Paul writes to the Galatians, who, after the gospel had been preached to them, wanted to live with the shadow, which is the law.… They had been taken in by a certain Ebion, who wanted to practice Judaism after having become a Christian and who was so successful in persuading others that the apostles gave him this surname to show his poverty. Ebion, in fact, means "poor," and he was so called because of the perversion and poverty of his ideas. As for the fact that the Galatians were of pagan origin, Paul writes, "Formerly, when you did not know God, you were in bondage to beings that by nature are not gods, but now you have come to know God, or rather to be known by God." He reproached them, as I said, in these terms (to produce now the text I announced): "Having begun with the Spirit, are you now ending with the flesh?" Indeed, when once they had given a wholly divine beginning to their edifice, they were looking for figures in an inappropriate manner, for they were searching for them when it was no longer their time. For we must understand why the visible circumcision was given and until what time it was appropriate to practice it. If one has understood this, he has had children from the concubine and is able, after this, to comprehend the circumcision of the heart that is effected by the Spirit. This holy man, upon the advice of virtue, went in to the slave girl whom she had placed at his disposal, as we have explained, and the slave girl conceived. But after this, it is inappropriate to remain with her beyond the time of her favor. Many indeed, having made use of the preparatory exercises in view of the perfect teaching, never go beyond this point, thus giving birth to a progeny of slavery, and in a certain sense dishonor virtue.… One dishonors virtue, then, who gives other things precedence over it. For if one chooses virtue, not for its own sake but for the sake of something else—praise, for example, or glory—then in a certain sense one is dishonoring the good, which in itself is not susceptible to dishonor. — ON Genesis 237-38