John Calvin Commentary Genesis 29:30

"And he went in also unto Rachel, and he loved also Rachel more than Leah, and served with him yet seven other years." — Genesis 29:30 (ASV)

And he loved also Rachel more than Leah. No doubt Moses intended to exhibit the sins of Jacob, that we might learn to fear, and to conform all our actions to the sole rule of God’s word. For if the holy patriarch fell so grievously, who among us is secure from a similar fall, unless kept by the guardian care of God?

At the same time, it appears how dangerous it is to imitate the fathers while we neglect the law of the Lord. And yet the foolish Papists so greatly delight themselves in this imitation, that they do not scruple to observe, as a law, whatever they find to have been practiced by the fathers.

Moreover, they regard as fathers those who are worthy of such sons, so that any raving monk is of more importance to them than all the patriarchs. Leah was not without fault in being despised by her husband; and the Lord justly chastised her, because she, aware of her father’s fraud, dishonorably obtained her sister’s husband. But her fault forms no excuse for Jacob’s lust.