When Moses revealed God’s judgement upon Israel, the people decided to reverse field and attempt an attack on Canaan. Moses warned them that the attack would not be successful. They opted to try instead, but the ark of the covenant nor Moses left the camp. The people were defeated and driven back to Hormah. The Lord offers information relative to specific offerings that would be offered once they did come into Canaan.
While the defeat at the hands of the Canaanites was disappointing and unfortunate, it was a sign that God did not lie, but meant what He said about the judgement that was to be meted out against the doubters. However, God did not leave them here. He immediately gave them instructions concerning offerings to be offered inside the promised land. That confirmed that He also meant what He said about their children inheriting the land one day. They would need these instructions when they came into the land.
No matter what you are facing today, the promises of God are true and trustworthy. If He said something, He will perform it. Do not doubt Him. He will not fail!