RAV KOOK ON Shemot PART 1: Going To Peace

After agreeing to lead the Israelites out of Egypt, Moses took leave of his father-in-law. Jethro blessed Moses “Go in peace” (Ex. 4:18). Actually, Jethro said “Go to peace.” The Talmud (Berachot 64a) picks up on this fine nuance: “One who takes leave from his friend should not say ‘Go in peace’ (lech BE-shalom), but ‘Go to peace’ (lech LE-shalom). Jethro told Moses, ‘Go to peace’ — Moses went and succeeded in his mission. David told his son Absalom, ‘Go in peace’ — Absalom went and was hanged. When taking leave of the deceased, however, one should say, ‘Go in peace.'” What is the difference between these two salutations? Why is one appropriate for the living, and the second for the dead?