According to Moses, people knew that God was with the Israelites and took care of them because they could see special signs like a cloud and fire showing them the way. This made everyone understand that God was really close to his people and helped them all the time.
Numbers 14:14: And they will tell [it] to the inhabitants of this land: [for] they have heard that thou LORD [art] among this people, that thou LORD art seen face to face, and [that] thy cloud standeth over them, and [that] thou goest before them, by day time in a pillar of a cloud, and in a pillar of fire by night.
This verse says, "And he said, Thou canst not see my face: for there shall no man see me, and live," suggesting that God cannot be seen face to face, contradicting the claim in Numbers 14:14 that the LORD is seen face to face.
Exodus 33:20: And he said, Thou canst not see my face: for there shall no man see me, and live.