Mark McWhorter
In Joshua 7, the Israelites attacked Ai but were soundly defeated. God then revealed to Joshua that someone had taken items from Jericho. All the things of Jericho were to be burned. God considered this action by the disobedient person not only as sin but as stealing from Him.
Joshua learned from God that it was Achan who sinned. Achan and his family were punished by being put to death. Afterward, the Israelites went up against Ai again, and this time the Israelites defeated the city.
After they were finished with Ai, they traveled to the valley between Mount Gerizim and Mount Ebal. Moses had told Joshua to take the people there when they entered the land. Joshua was to read the Law to the people. He read all the blessings and the cursings. Half of the tribes stood in front of Mount Gerizim and half stood in front of Mount Ebal. The blessings were called out from Gerizim, while the cursings were called out from Ebal (Joshua 8:33).
These were given to educate and encourage the people to obey God. We also need to obey God. The only way to be blessed by God with spiritual blessings and with eternal life in Heaven is to obey Him.
Study your Bible. Learn how to obey God. If any of this is hard to understand, ask an adult to help you.