Deuteronomy 21:15

If a man has two wives, one greatly loved and the other hated, and the two of them have had children by him; and if the first son is the child of the hated wife:

Genesis 29:33

Then she became with child again, and gave birth to a son; and said, Because it has come to the Lord's ears that I am not loved, he has given me this son in addition: and she gave him the name Simeon.

1 Samuel 1:4-5

And when the day came for Elkanah to make his offering, he gave to Peninnah his wife, and to all her sons and daughters, their part of the feast:

Genesis 29:18

And Jacob was in love with Rachel; and he said, I will be your servant seven years for Rachel, your younger daughter.

Genesis 29:20

And Jacob did seven years' work for Rachel; and because of his love for her it seemed to him only a very little time.

Genesis 29:30-31

Then Jacob took Rachel as his wife, and his love for her was greater than his love for Leah; and he went on working for Laban for another seven 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 was in love with Rachel; and he said, I will be your servant seven years for Rachel, your younger daughter.
1 Samuel 1:4
And when the day came for Elkanah to make his offering, he gave to Peninnah his wife, and to all her sons and daughters, their part of the feast:

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain