In his famous work, Path of the Righteous, Rabbi Moshe Chaim Lazatto teaches that three types of people speak falsehood. 1) Someone who lies all the time, 2) a person who speaks intermittently falsehood, and 3) an individual who keeps from deliberately lying but when in need or when an external factor arises he will be prompted to lie. The Torah teaches us to distance ourselves very far from falsehood.
Yehuda has promised his father Jacob that he will return Benyamin his brother back to his father. The second in command of all of Egypt, the viceroy, has accused Benyamin of stealing a wine goblet from the palace. Yehuda is now tasked with pleading for Benyamin's freedom. Our sages tell us that "fear" is in play (see Rashi)
Yehuda recounts prior events to the viceroy and in his recount, he says that Benyamin's maternal brother, Yosef, is dead. Yehuda does not know this to be the reality but fear leads him to lie in his attempt at saving his brother.
"[Yehuda expressed], 'And we (the brothers) said to my lord (the viceroy of Egypt), 'We have an old father and a young child, Benyamin, of Jacob's old age; Benyamin's brother is dead, he alone is left to his mother, and his father loves him." Genesis 44:20, from this week's Torah portion, Vayigash, Genesis 44:18-47:27