וַתַּהַר עוֹד וַתֵּלֶד בֵּן וַתֹּאמֶר עַתָּה הַפַּעַם יִלָּוֶה אִישִׁי אֵלַי כִּֽי־יָלַדְתִּי לוֹ שְׁלשָׁה בָנִים עַל־כֵּן קָֽרָא־שְׁמוֹ לֵוִֽי
And she conceived again, and bore a son; and said, Now this time will my husband be joined to me, because I have born him three sons; therefore was his name called Levi.
When a woman has one child, she holds it in both arms. When another child is born, she holds one in her right arm and the other in her left. But when there are three small children, her husband must help her hold them.
Thus, when Leah held her third son, she said: “This time, my husband will be joined to me: Now my husband will have to help me, because I have borne him three sons and I cannot hold them all myself.”