In chapter 3, Paul lays out a warning to these Jewish believers: We can lose the reward of our inheritance in Christ if we lose our hope and harden our hearts. Paul uses the Israelites as an example of a people who hardened their hearts against God and against repentance, and as a result, that generation did not receive the inheritance of the promised land.
Jesus was faithful to God just as Moses was faithful to God. Moses was faithful in God’s house as a servant but Jesus was faithful as a Son – the Inheritor. We can be a part of God’s household that inherits as well, if we hold fast.
Paul gives the example of the Israelites’ refusal to trust God that resulted in wandering in the desert for 40 years and never being able to enter the land that God promised them.
Paul continues warning these believers to not turn away from God. He asks them to encourage one another and turn from sin.
The Israelites turned from God, and because of their unbelief, they did not receive their inheritance.