Mussar from the Parsha: Yitro

לֹא יִהְיֶה לְךָ אֱלֹהִים אֲחֵרִים עַל פָּנָי

שמות כ:ג

Exodus Chapter 20
3. You shall have no other gods before Me.

They asked Rabbi Menachem Mendel of Kotzk: What new thing did King David tell us when he said (Psalms 81:10): “There shall not be a strange god in your midst”? Is there not an explicit commandment that “you shall not have other gods”?

He answered: King David’s intention was that you shall not have within yourself a God who is “strange” - a stranger to you. Rather, God’s presence should dwell within you in your heart at all times.