Genesis 29:18

And Jacob loved Rachel; and said, I will serve thee seven years for Rachel thy younger daughter.

Jacob loved Rachel, Laban's younger daughter, and agreed to serve Laban seven years in order to marry her. His offer of labor stood in place of money or property as the bride-price or dowry, following the custom by which a suitor who had no money, property, or other wealth or valuable property could work for the bride's father for a set time instead. The length of that required service was set according to the dowry required, with the time related to its amount.

That service tested and showed the suitor's diligence and ability, his faithfulness, his worth and worthiness, his ability to provide, and the depth of his affection before marriage. The arrangement was meant to safeguard marriage and help prevent a hasty marriage, so that faithful service and judged worthiness led to marriage. A dowry received in this way was generally given to the daughter when she married. Laban afterward deceived Jacob by giving him Leah instead of Rachel. He also kept for himself the dowry that should have been given to Rachel and Leah.

Jacob's affection motivated faithful service, and his love made the work seem light. For Rachel's sake he ultimately served twice seven years. The depth and lasting strength of his love were shown by how deeply he mourned Rachel and remembered her death.