After Yaakov Avinu heroically removes a boulder from the well of Charan and is thanked by Rachel, Lavan, Yaakov's uncle, hears the news and goes out to greet his nephew. Yaakov accepts Lavan’s offer of lodging and works for Lavan for a month; Lavan agrees to marry off either of his daughters -- Leah or Rachel -- to Yaakov as payment for an extended period of labor (BeReishit 29:1-17). When the Torah describes both Leah and Rachel’s physcial charact it seems to be cruelly judgmental, describing that “VeEinei Le’ah Rakot, VeRachel Hayetah Yefat To’ar Vi’fat Mar’eh”, “Leah had weak eyes; Rachel was beautiful” (BeReishit 29:17). Why would the Torah use such degrading words to describe the older sister, but go out of its way to effusively praise the looks of the younger? Shouldn’t the Torah present the description of the sisters without any sort of pre-existing bias towards Rachel?
Chazal (Tanchuma Buber 12:1) teach us that Leah and Rachel were in fact equal in beauty, but Leah’s eyes were weakened due to a more practical reason. When Rivka bore Esav and Yaakov, and Lavan’s wife bore Leah and Rachel, Lavan and Yitzchak arranged that both their two eldest and two youngest would get married. As the years passed, Leah became increasingly worried about the prospect of marrying Ya’akov’s eldest, Eisav. Leah would constantly cry at the thought of marrying such a Rasha like Eisav, which in effect weakened her eyes.
This is the Midrashic view of the Pasuk. Rashi (BeReishit 29:18), however, explains that the Torah didn’t emphasize Rachel’s prettiness to contrast with Leah’s lack thereof; rather the Torah elaborates on Rachel’s beauty to portray the thoughts that were running through Yaakov’s head. Yaakov knew Lavan was a deceiver. By paying careful attention Rachel’s physical characteristics, Yaakov thought that he would be able to distinguish one sister from the other and not get tricked by Lavan, as he eventually did. The Pasuk highlights how Yaakov believed that he had determinied the difference between the sisters, and was nonetheless tricked by Lavan.
Rashi’s comment implies that Lavan’s trickery was not just a one time event, rather it seemed to be Lavan’s defining vice. The first time the Torah introduces Lavan, he is called “Lavan ben Nachor”, “Lavan the son of Nachor.” (ibid. 29:5). Even though Betuel was Lavan’s father (cf. 28:5), the Torah strangely writes that he was the son of Nachor. Radak (ad. loc.) explains that Nachor, Lavan’s grandfather, was a well known and honored man unlike Lavan’s father Betuel. For his self image and credentials, Lavan must have exploited his grandfather's good name, and the lie perpetrated about his paternity was to be but the first of many acts of deception committed by Lavan. Rashi (ibid. 29:13) presents another example of Lavan’s selfishness. When Lavan hears that his nephew Yaakov is in town, he excitedly rushes over to greet and kiss Yaakov. Rashi explains that Lavan was running over to Yaakov in the hope that Yaakov brought camels laden with gold to give as presents, just like Eliezer had done in the past for his sister Rivkah (24:53). When Lavan hugged and kissed Yaakov, it was not a measure of goodwill; it was done to determine if Yaakov was carrying gold or precious stones on his body.
Furthermore, the Da'at Zekenim (29:22) explains that the giant party Lavan made to celebrate Yaakov’s supposed wedding with Rachel was just another example of Lavan’s deception. He threw the lavish party in order to intoxicate Yaakov Avinu, and ensure he would be unable to distinguish between Leah and Rachel.
These numerous examples of Yaakov being tricked beg the question of why Hashem would let the Yaakov Avinu, the “Ish Tam”, “blameless man” (25:27), be constantly deceived, and specifically in the case of Leah and Rachel, where Yaakov had the means to distinguish between the two sisters. The Da’at Zekeinim (29:25) explains that when Yaakov realized what happened in the morning, he immediately confronted Leah about the deceptive marriage. Her response was that she and her father had actually learned the art of trickery from Yaakov -- Yaakov obtained the firstborn blessing by tricking his father into believing that he was Eisav. Therefore, Leah felt justified in fooling Yaakov into marrying her, instead of Rachel.
The fact that Leah acted based on an episodes which occurred far in Yaakov’s past -- over seven years, to be exact (29:20 and more according to Chazal) -- illustrates the importance of our behaving as best as we can, because the smallest action can have an immense effect on the observer’s conduct towards others. Even though you may believe that no one is paying attention, there will be people looking to you and emulating your actions. As righteous as Yaakov was and as noble his intentions in marrying Rachel were, an unsavory moment from his past caused him great trouble in his stay with Lavan, forcing him to spend an extra seven years working for Lavan to marry Rachel (29:28). We should learn from Yaakov Avinu’s mistake, and throughout our everyday conduct, we should be mindful of its long term effect and impact on how others might act towards us as a result.