Genesis 27:5

5. And Rebekah heard. Moses now explains more fully the artifice by which Jacob attained the blessing. It truly appears ridiculous, that an old man, deceived by the cunning of his wife, should, through ignorance and error, have given utterance to what was contrary to his wish. And surely the stratagem of Rebekah was not without fault; for although she could not guide her husband by salutary counsel, yet it was not a legitimate method of acting, to circumvent him by such deceit. For, as a lie is in itself culpable, she sinned more grievously still in this, that she desired to sport in a sacred matter with such wiles. She knew that the decree by which Jacob had been elected and adopted was immutable; why then does she not patiently wait till God shall confirm it in fact, and shall show that what he had once pronounced from heaven is certain? Therefore, she darkens the celestial oracle by her lie, and abolishes, as far as she was able, the grace promised to her son. Now, if we consider farther, whence arose this great desire to bestir herself; her extraordinary faith will on the other hand appear. For, as she did not hesitate to provoke her husband against herself, to light up implacable enmity between the brothers, to expose her beloved son Jacob to the danger of immediate death, and to disturb the whole family; this certainly flowed from no other source than her faith. The inheritance promised by God was firmly fixed in her mind; she knew that it was decreed to her son Jacob. And therefore, relying upon the covenant of God, and keeping in mind the oracle received, she forgets the world. Thus, we see, that her faith was mixed with an unjust and immoderate zeal. This is to be carefully observed, in order that we may understand that a pure and distinct knowledge does not always so illuminate the minds of the pious as to cause them to be governed, in all their actions, by the Holy Spirit, but that the little light which shows them their path is enveloped in various clouds of ignorance and error; so that while they hold a right course, and are tending towards the goal, they yet occasionally slide. Finally, both in Isaac and in his wife the principle of faith was preeminent. But each, by ignorance in certain particulars, and by other faults, either diverged a little from the way, or, at least, stumbled in the way. But seeing that, nevertheless, the election of God stood firm; nay, that he even executed his design through the deceit of a woman, he vindicates, in this manner, the whole praise of his benediction to his own gratuitous goodness.