Exodus 24: 3. . . . ‘All the words which the LORD hath spoken will we do.’ With all they(Hebrews and those with them) saw and experienced up to this moment, they still made an idol and worshiped it.
Belief is a motivator.
Knowledge of GOD, while it is not required, as long as you are willing to keep HIS LAWS and TEACHINGS in all things. However, from the beginning we humans, being created from the dust to transport the BREATH OF GOD(soul) have been in need of more justification, and encouragement not to give in to our dirt(evil).
When we have this knowledge of GOD, a realization of just how small I am and how important I am, provide greater motivation for self-control. It is still possible to give-in to the dirt, but we are better equipped and motivated not to give in.
Yaakov