Numbers 19:1 to 22:1, Judges 11:1-33
The ceder, hyssop, and a scarlet thread are not only to be burned with the red cow, but are also part of the Metzora ritual (Leviticus 14:4). Both situations are about becoming ritually pure from death: physical death in Numbers 19 and spiritual death in Leviticus 14.
The "water of purification" is strange stuff. It can make ritually potent those who have had contact with death. But, alone among the products of offerings, it contains skin and dung and thus contaminates anyone else. This is a foreshadowing of the Good News that Yeshua taught: we can move from "spiritual death" to "spiritual life", but doing so requires us to deal with the refuse in our souls.
Moses's sin happened immediately after his sister Miriam's death. Perhaps his grief had been overwhelming enough he was no longer completely focused on God. Or perhaps he had to be actively doing something to the rock that gave water, and while greiving he had stopped this maintenance.
The K'li Yakar claims that the Israelite's weeping for Miriam's death was punished by the miraculous rock halting its stream of water.
Mount Hor, hor ha'har, literally means "mount of mountains" (a similar grammatical structure to "king of kings"). This was probably the tallest mountain in the area, taller than Sinai. The contrast shows that God is higher than people but descends to meet with us, yet after we die we ascend to a level higher than where we met with God while before death.
In Eden, the snake was cursed so that all it ate tasted like dirt, because it convinced Havah to eat what she should not. Now the Israelites, for complaining that the mana tasted contemptible and urging each other to eat what they should not, have snakes punish them. The bronze snake is truly strange: it was not worshipped, merely looked at, and it did not remove the real snakes but only made their poison ineffective.
Verses 21:10-15 describe locations based upon the rivers of the land, in contrast to verses 33:44-47 which describe the same places based upon cities and mountains. In this way chapter 21 sets up a contrast between the water God gives the Israelites and the water flowing from the land of their foes.
Why was Moses punished? At the Red Sea the people were full of faith (Ex. 14:31). When their faith was high striking a rock was proper (Ex. 17). But after the incident with the spies the people's faith was very low (Num. 14:11, Deut. 1:32). By striking the rock with his staff then Moses was drawing too much attention to the staff, instead of to God (Num. 20:12). Moses was punished because his actions could have potentially restored the people's faith to a high level, but he did something different from what God commanded that did not restore the people's faith.
Some sages say that the sin of Moshe and Aharon was that they said notzee la'chem mayim, "We will draw out for you water", as if Moshe and Aharon could do so in their own cleverness and power. For this reason God was angry at them, for purposefully or not they had taken credit for the action.
Tradition says that in the future days of the Messiah, when the dead are raised, the generations of Israel that died in the desert will again stand, and Moshe will rise, and he will finally lead the worthy ones into the Promised Land.
One story tells that a miracle happened upon Mount Hor when Aharon dies and his son Elazar became high priest: Moshe was able to remove the priestly garments "inside out", starting with the shirt that was closest to Aharon's body; in this way Elazar could put on the garments in the correct order without the garments having to be placed on the ground.
The Tz'enah Ur'enah comments on verse 21:8, where the people of Israel admit their sin to Moshe and ask him to pray for them, that
We learn from this that a person should not harden himself against forgiving, and even if people spoke against him, he should be quick to forgive when pardon is sought. If he does not forgive, he is called unmerciful, and God will not forgive him either. We see that even though Israel spoke much against Moshe, whenever they asked him for forgiveness he immediately forgave and pleaded with God on their behalf.
A person who has sinned should not think that God will not forgive him, for God is merciful and forgives those who ask for pardon.