Chapter 19 records the commands for the provision of a red heifer which is to be slaughtered and its blood sprinkled toward the tent of meeting and its body burnt. Its ashes are to be kept for use in the water of cleansing. Anyone who touches a dead body was unclean and needed to use the water to cleanse themselves. In chapter 20 they arrive at the Desert of Zin where Miriam died. The people had no drinking water and complained against Moses again. God promised to supply water saying, “Speak to that rock before their eyes and it will pour out its water” (20:8). Unfortunately, instead of speaking to the rock, Moses hit it twice with his staff. Water still gushed out but God was displeased and announced that Moses and Aaron would not be alive to lead the people into the promised land.
Israel then intended to pass through Edom but the Edomites refused them passage and threatened them with war. They came to Mount Hor where Aaron died. Eleazar went up the mountain with Moses and Aaron and the priestly garments were transferred. The people then mourned for Aaron for 30 days which fit his station but is surprising given how much grief he suffered at the hands of these people.
The Canaanite king of Arad went out and attacked the Israelites but they were defeated and Israel completely destroyed their towns. As they bypassed Edom they again began to complain and this time God send poisonous snakes among them. The people saw the error of their ways and cried out for God to relent. “The Lord said to Moses, ‘Make a snake and put it up on a pole; anyone who is bitten can look at it and live.’ So Moses made a bronze snake and put it up on a pole. Then when anyone was bitten by a snake and looked at the bronze snake, they lived” (21:8-9). This snake on a pole preconfigured Christ who would be lifted up on a pole (the cross) for the salvation of all.
The people of Israel come into more and more conflict with the residents of this area. They asked Sihon, king of the Amorites, for passage and he refuses and attacks. Israel defeated his army and captured his towns. Og, king of Bashan, also came out in battle but was defeated and his land taken.