THE DEATH OF NADAB AND ABIHU

Now Nadab and Abihu, the sons of Aaron, took their respective [ceremonial] censers, put fire in them, placed incense on it and offered strange (unauthorized, unacceptable) fire before the LORD, [an act] which He had not commanded them to do.
And fire came out from the presence of the LORD and devoured them, and they died before the LORD.

LAW OF THE BURNED OFFERING

Law of the burned-offering. “Command Aaron and his sons, saying, ‘This is the law of the burnt offering: the burnt offering shall remain on the hearth that is on the altar all night until morning and the fire is to be kept burning on the altar.

MOSES BREAKS THE TABLES AND BURNS THE GOLDEND CALF

Moses breaks the tables and burns the golden calf. And as soon as he approached the camp and he saw the calf and the dancing, Moses’ anger burned; and he threw the tablets from his hands and smashed them at the foot of the mountain.
Then Moses took the calf they had made and burned it in the fire, and ground it to powder, and scattered it on the surface of the water and made the Israelites drink it.

THE MURMURING PEOPLE ENCOURAGED

Then Moses said to the people, “Do not be afraid! Take your stand [be firm and confident and undismayed] and see the salvation of the LORD which He will accomplish for you today; for those Egyptians whom you have seen today, you will never see again.

PILLARS OF CLOUD AND FIRE

Pillars Of Cloud And Fire. The [presence of the] LORD was going before them by day in a pillar (column) of cloud to lead them along the way, and in a pillar of fire by night to give them light, so that they could travel by day and by night.
He did not withdraw the pillar of cloud by day, nor the pillar of fire by night, from going before the people.