Philo Judaeus De Congressu Eruditionis Gratia 78

[78] for each act has its own peculiar brilliancies, certain attractive powers, by which some persons are allured and overcome, forgetting all the covenants which they have made with philosophy; but he who abides by the agreements which he has made, provides every thing from all quarters with a view to pleasing her. Very appropriately, therefore, does the sacred scripture, admiring his good faith in respect of his legitimate wife, say that even now Sarah was his true wife, inasmuch as he only took his handmaid into his bed out of complaisance towards her;