When Yakov disguised himself to receive his Yitzchak’s blessing, he had to quell Yitzchak’s suspicions:
וַיֹּאמֶר יַעֲקֹב אֶל אָבִיו אָנֹכִי עֵשָׂו בְּכֹרֶךָ עָשִׂיתִי כַּאֲשֶׁר דִּבַּרְתָּ אֵלָי קוּם נָא שְׁבָה וְאָכְלָה מִצֵּידִי בַּעֲבוּר תְּבָרֲכַנִּי נַפְשֶׁךָ – Yakov said to his father, “I am, Esau, your firstborn. I have done as you said to me. Please rise, sit down and eat, so that you can bless me.” (27:19)
Isn’t this an outright lie?
When this story is taught to youngsters, they learn that he did not claim to be Esau. Yakov paused after he said “I am”, and then simply affirmed that Esau was his firstborn son.
But when he said “I have done as you said to me,” what other way is there to understand the deception?
Rashi states that although it seems like he lied, Yakov was still being true to Yitzchak’s ways. The Od Yosef Chai notes that Avraham taught Yitzchak, and Yitzchak taught Yakov. Yakov could truthfully state he had done as Yitzchak had said. Undoubtedly, one of the instructions was to honour his parents, and in fact, the whole scheme was his mother’s idea! He listened to his mother because his father had taught him to.
It’s a fine line. But sometimes it’s more important to stay true to what something means than to keep to what it literally says.