Genesis 29:25
And it came to pass, that in the morning, behold, it was Leah: and he said to Laban, What is this thou hast done unto me? did not I serve with thee for Rachel? wherefore then hast thou beguiled me? And it came to pass, that in the morning, behold, it was Leah: and he said to Laban, What is this thou hast done unto me? did not I serve with thee for Rachel? wherefore then hast thou beguiled me?
After seven years of service for Rachel, Jacob was given Leah instead by Laban's deception, which he discovered in the morning. Jacob's labor was the bride-price for Rachel, following the custom where a suitor without money or property worked for the bride's father for a set time reflecting the required dowry, an arrangement that tested his ability and faithfulness before marriage. When he discovered the substitution, he confronted Laban for deceiving him, betraying his trust and trifling with his affections.
Laban acted selfishly to keep the benefit of Jacob's faithful service, and he kept for himself the dowry that should have gone to his daughters. He excused the substitution by appealing to family custom and to the disgrace of sending Leah away. Jacob remained married to Leah and also married Rachel, keeping Leah as his wife while serving another seven years for Rachel, for fourteen years of service in all.
Jacob's love for Rachel made the toil light, and those fourteen years measure how deep and abiding his love was, lasting through his long and troubled life so that at its end the loss of Rachel was alone recalled in his family history. Leah had taken part in the deception, so Jacob loved her much less than Rachel and felt unable to love her, and his preference for Rachel led to envy and jealousy between the sisters that embittered his life.