Deuteronomy 21:15

If a man has two wives, the one beloved, and the other regarded inferior, and they have borne him sons, both the beloved and the one regarded inferior, and if the first-born son be hers who was regarded inferior,

Genesis 29:33

And she conceived again, and bore a son, and said, Because LORD has heard that I am regarded inferior, he has therefore given me this [son] also. And she called his name Simeon.

1 Samuel 1:4-5

And when the day came that Elkanah sacrificed, he gave to Peninnah his wife, and to all her sons and her daughters, portions,

Genesis 29:18

And Jacob loved Rachel, and he said, I will serve thee seven years for Rachel thy younger daughter.

Genesis 29:20

And Jacob served seven years for Rachel. And they seemed to him but a few days, for the love he had for her.

Genesis 29:30-31

And he also went in to Rachel, and also he loved Rachel more than Leah, and served with him yet seven other years.

Treasury of Scripture Knowledge

Summary

If a man have two wives, one beloved, and another hated, and they have born him children, both the beloved and the hated; and if the firstborn son be hers that was hated:

Bible References

Two wives

Genesis 29:18
And Jacob loved Rachel, and he said, I will serve thee seven years for Rachel thy younger daughter.
1 Samuel 1:4
And when the day came that Elkanah sacrificed, he gave to Peninnah his wife, and to all her sons and her daughters, portions,