In Jewish sources, our forefather Yaakov is always identified with the character trait of honesty, of dedicating himself to truth. Sometimes this seems difficult to understand — after all, he deceived his father in order to claim the blessings of the firstborn son. So how can he be considered so honest?
To understand Yaakov’s strength of character and dedication to this trait, we need only look at his rebuke to his father-in-law Lavan. He decides to leave Lavan’s camp quietly, because he detects that his father-in-law is becoming hostile. But when Lavan discovers that Yaakov and his family have left, he pursues them. Yaakov then says to him, “what is my sin that you have chased after me?” [31:36] Lavan searched through the entire camp (he was looking for his idols, which Rachel had indeed taken without anyone’s knowledge), and Yaakov tells Lavan to lay out anything he has found that he believes to be his — for there is nothing to be found.
After all, Yaakov continues, he served Lavan faithfully for twenty years. During that time, his only wages were the animals that were born dark, spotted, or patched with color. And if any animal died in Yaakov’s care, he deducted it from his own wages.
And then he reminds Lavan, “you changed my wages one hundred times” [31:41 — see Rashi to 31:7]. When Lavan saw how well Yaakov was doing, he kept changing the deal for his own benefit. When many sheep were born spotted, he said “you take the dark ones and I’ll take the spotted ones.” And when the sheep immediately started giving birth to dark ones instead, he told Yaakov, “you take the patched ones.”
During all that time, as Lavan kept trying to take away from Yaakov that which he had earned, Yaakov remained completely faithful. He could easily have said, “the loss of that sheep wasn’t my fault, and Lavan will never notice” — yet every time, he took responsibility.
Sometimes, even a completely honest person must hide the truth. A careful reading of the verses shows that Yaakov did not lie to his father. He was simply claiming the blessing that was his, for he had purchased the birthright of the firstborn from Esav. He did not want to tell his father that Esav had sold away the birthright, and left it for G-d to reveal this prophetically to Yitzchak.
That was, however, for a spiritual matter, to receive the blessing that was appropriate for the father of the Jewish nation. When it came to business, no deceit on his part was tolerated, no matter how obvious the deceit from his partner. The evidence of Yaakov’s religiosity, of his dedication to G-d, was not found in how long he prayed, or how strictly he kept Kosher — but in how he ran his business.