Genesis 29:31 When the LORD saw that Leah was hated, he opened her womb, but Rachel was barren. And Leah conceived and bore a son, and she called his name Reuben, for she said, “Because the LORD has looked upon my affliction; for now my husband will love me.” She conceived again and bore a son, and said, “Because the LORD has heard that I am hated, he has given me this son also.” And she called his name Simeon. Again she conceived and bore a son, and said, “Now this time my husband will be attached to me, because I have borne him three sons.” Therefore his name was called Levi. And she conceived again and bore a son, and said, “This time I will praise the LORD.” Therefore she called his name Judah. Then she ceased bearing.
30:1 When Rachel saw that she bore Jacob no children, she envied her sister. She said to Jacob, “Give me children, or I shall die!” Jacob’s anger was kindled against Rachel, and he said, “Am I in the place of God, who has withheld from you the fruit of the womb?” Then she said, “Here is my servant Bilhah; go in to her, so that she may give birth on my behalf, that even I may have children through her.” So she gave him her servant Bilhah as a wife, and Jacob went in to her. And Bilhah conceived and bore Jacob a son. Then Rachel said, “God has judged me, and has also heard my voice and given me a son.” Therefore she called his name Dan. Rachel’s servant Bilhah conceived again and bore Jacob a second son. Then Rachel said, “With mighty wrestlings I have wrestled with my sister and have prevailed.” So she called his name Naphtali. When Leah saw that she had ceased bearing children, she took her servant Zilpah and gave her to Jacob as a wife. Then Leah’s servant Zilpah bore Jacob a son. And Leah said, “Good fortune has come!” so she called his name Gad. Leah’s servant Zilpah bore Jacob a second son. And Leah said, “Happy am I! For women have called me happy.” So she called his name Asher.
In the days of wheat harvest Reuben went and found mandrakes in the field and brought them to his mother Leah. Then Rachel said to Leah, “Please give me some of your son’s mandrakes.” But she said to her, “Is it a small matter that you have taken away my husband? Would you take away my son’s mandrakes also?” Rachel said, “Then he may lie with you tonight in exchange for your son’s mandrakes.” When Jacob came from the field in the evening, Leah went out to meet him and said, “You must come in to me, for I have hired you with my son’s mandrakes.” So he lay with her that night. And God listened to Leah, and she conceived and bore Jacob a fifth son. Leah said, “God has given me my wages because I gave my servant to my husband.” So she called his name Issachar.
And Leah conceived again, and she bore Jacob a sixth son. Then Leah said, “God has endowed me with a good endowment; now my husband will honor me, because I have borne him six sons.” So she called his name Zebulun. Afterward she bore a daughter and called her name Dinah.
Then God remembered Rachel, and God listened to her and opened her womb. She conceived and bore a son and said, “God has taken away my reproach.” And she called his name Joseph, saying, “May the LORD add to me another son!”
Wow, two wives and two servants gave birth to 10 sons of Jacob. This seems that it would be a bit complicated to manage for anyone. I do note that just as Sarah and Rebekah were barren for a time and gave birth through and by the promise of God, Rachel likewise was barren for a time until God gave her children.
These are the 11 sons (one more to come) of Jacob; Reuben, Simeon, Levi, Judah, Dan, Naptali, Gad, Asher, Issachar, Zebulun, and Joseph.
Leah’s First Sons. – Jacob’s sinful weakness showed itself even after his marriage, in the fact that he loved Rachel more than Leah; and the chastisement of God, in the fact that the hated wife was blessed with children, whilst Rachel for a long time remained unfruitful. By this it was made apparent once more, that the origin of Israel was to be a work not of nature, but of grace. Leah had four sons in rapid succession, and gave them names which indicated her state of mind: (1) Reuben, “see, a son!” because she regarded his birth as a pledge that Jehovah had graciously looked upon her misery, for now her husband would love her; (2) Simeon, i.e., “hearing,” for Jehovah had heard, i.e., observed that she was hated; (3) Levi, i.e., attachment, for she hoped that this time, at least, after she had born three sons, her husband would become attached to her, i.e., show her some affection; (4) Judah (יהוּדה, verbal, of the fut. hoph. of ידה), i.e., praise, not merely the praised one, but the one for whom Jehovah is praised. After this fourth birth there was a pause (Genesis 29:31), that she might not be unduly lifted up by her good fortune, or attribute to the fruitfulness of her own womb what the faithfulness of Jehovah, the covenant God had bestowed upon her. (Keil and Delitzsch)
Rachel envied her sister: envy is grieving at the good of another, than which no sin is more hateful to God, or more hurtful to our neighbours and ourselves. She considered not that God made the difference, and that in other things she had the advantage. Let us carefully watch against all the risings and workings of this passion in our minds. Let not our eye be evil towards any of our fellow-servants, because our Master’s is good. Jacob loved Rachel, and therefore reproved her for what she said amiss. Faithful reproofs show true affection. God may be to us instead of any creature; but it is sin and folly to place any creature in God’s stead, and to place that confidence in any creature, which should be placed in God only. At the persuasion of Rachel, Jacob took Bilhah her handmaid to wife, that, according to the usage of those times, her children might be owned as her mistress’s children. Had not Rachel’s heart been influenced by evil passions, she would have thought her sister’s children nearer to her, and more entitled to her care than Bilhah’s. But children whom she had a right to rule, were more desirable to her than children she had more reason to love. As an early instance of her power over these children, she takes pleasure in giving them names that carry in them marks of rivalry with her sister. See what roots of bitterness envy and strife are, and what mischief they make among relations. At the persuasion of Leah, Jacob took Zilpah her handmaid to wife also. See the power of jealousy and rivalship, and admire the wisdom of the Divine appointment, which joins together one man and one woman only; for God hath called us to peace and purity. (Henry)