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 Vous observerez mes commandements, et vous ne pratiquerez aucun des usages abominables qui se pratiquaient avant vous, vous ne vous en souillerez pas. Je suis l'Eternel, votre Dieu.