A Sicha for Parashat Vayigash

Rabbi Aharon Lichtenstein delivers a sicha about Yosef's words to his brothers on their way back to Canaan: "Do not get distressed on the way." The simple meaning of the Hebrew verse seems to connote turmoil, fear, or anxiety - and that Yosef is trying to calm his brothers with a soothing message. Rashi, however, explains the verse as meaning "do not deal with Halakha on the way." What does this mean?