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. That bigamy, polygamy, is a perversion of God's original order, since marriage is to be a monogamy, the union of one man and one woman, appears even here, for it was impossible for Jacob to distribute his affections with impartiality. In spite of the fact, therefore, that the blessing of God upon Abraham made use also of these means to make of the descendants of Abraham a great nation, it is clear, nevertheless, that much of the subsequent trouble was due to this unnatural arrangement.