A true Oved Hashem

The Beis HaLevi asks why the Torah keeps repeating "as Hashem commanded" in the building of the Mishkan, and connects it to two more puzzles. How did the generation that saw the sea split fall into the golden calf? And why was the Akeidah a test for Avraham at all, when Hashem himself gave the command? One answer covers all three. A king's instruction to his ambassador, just one small thing not to do, reveals what is at stake in being an eved Hashem.