For twenty years Jacob remained in Mesopotamia, laboring in the service of Laban, who, disregarding the ties of kinship, was bent upon securing to himself all the benefits of their connection. Fourteen years of toil he demanded for his two daughters; and during the remaining period, Jacob's wages were ten times changed. Yet Jacob's service was diligent and faithful. His words to Laban in their last interview vividly describe the untiring vigilance which he had given to the interests of his exacting master: "This twenty years have I been with thee; thy ewes and thy she-goats have not cast their young, and the rams of thy flock have I not eaten. That which was torn of beasts I brought not unto thee; I bare the loss of it; of my hand didst thou require it, whether stolen by day, or stolen by night. Thus I was; in the day the drought consumed me, and the frost by night; and my sleep departed from mine eyes."

Jakob ydede syv års tro tjeneste for Rakel, "og de syntes ham kun nogle få dage, fordi han elskede hende". Men den egenkærlige, begærlige Laban ønskede at beholde sin værdifulde hjælper og bedrog ham på det grusomste ved at give ham Lea i stedet for Rakel. Lea havde i virkeligheden selv andel i bedrageriet, og dette bevirkede, at Jakob følte, at han ikke kunne elske hende. Hans harmfulde bebrejdelse mod Laban blev imødegået af tilbudet om Rakel, hvis han ville arbejde endnu syv år. Men faderen holdt fast på, at Lea ikke skulle tilsidesættes, da det ville kaste vanære over familien. Derved blev Jakob bragt i en meget pinlig og vanskelig situation. Til sidst besluttede han at beholde Lea og gifte sig med Rakel også. Han elskede hele tiden Rakel mest; men hans forkærlighed for hende vakte søsterens skinsyge og misundelse, og hans ægteskabelige liv blev forbitret af de to søstres rivaliseren.