Israel complains with no water. God tells Moses to speak to the rock to give water. Moses hits it instead, also claiming ability himself to bring water. God still lets the water come, but punishes Moses with no entry to Canaan personally. Israel asks Edom nicely to pass through but they say no. Israel goes around. Aaron dies and Eleazar replaces him as high priest.
Israel conquers Canaanite Arad after it attacks and kidnaps some Israelites. Israel complains against God again, and He sends snakes and then gives a way to be saved from their death. They pass through Beer(Sheba?) where there is a well of water they appreciate. They ask the Amorites to pass through, but they attack instead. Israel wins, and also conquers Bashan.
The Moabite King Balak next door gets nervous and calls for a prophet Balaam to curse Israel. God tells him not to go at first, to emphasize that Balaam needs to listen to Him. Then God's angel appears to his donkey and it talks to him, to get Balaam's attention again, because his heart is still not committed to saying what God says to say. He goes to Balak but is now more loyal to God than to the paying customer Balak.
How this is about Jesus
Jesus is the rock that gave Israel water (1 Cor. 10:1-5). Interesting Moses hits it/Him.
Jesus is lifted up on a stake, like God has Moses do with the snake (John 3:14-15). It is a picture of Satan crushed for good, by Jesus being crushed for a while.
Jesus tests some Gentiles while ministering on earth, as God tests Balaam, finding them faithful at least to speak the truth about God.
Sins this reveals
We go back to complaining as often as circumstances deteriorate, even temporarily, not learning from history that God will provide for us.
We pursue enterprises and opportunities for our own self interest, regardless of God's take on it.