Why did Israel wander in the wilderness for 40 years if God gave them a valid offer?
Israel wandered forty years because, although God gave a valid offer to enter the promised land at Kadesh Barnea, He knew beforehand they would not go in. Their refusal did not negate the offer's validity; the wilderness period was included in God's divine purpose and plan.
Les explains that God made a valid offer to the nation of Israel and was not playing games with them. They could have gone into the promised land—the milk and honey at Kadesh Barnea. God told them to go in and take the land; He would drive out the Canaanites with hornets, the land was already in production, and all they had to do was take it over. He would drive the inhabitants out slowly so weeds would not take over first. Israel did not do it, but the offer was still valid. God knew they would not go in. Therefore the whole divine purpose of the 40-year wilderness was in His divine plan, not a sign that He had failed to give them a valid offer. Les also ties this to God's eternal purpose and grace in Christ Jesus, not according to works or through the nation of Israel.