The final exhortation is to be understood as a divine charge. The word charge
(mišmār) is derived from the verb that means, to watch over
or to guard.
The Israelites are to conduct themselves in this manner as an expression of obedience, but also to protect future generations.
30 So keep my charge never to practice any of these abominable customs that were practiced before you, and never to make yourselves unclean by them: I am the LORD your God.”