Hebrews 3 Commentary

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 as inheritors as well, if we hold fast. 

The Pauline Author gives the example of the Israelites' refusal to trust God. Their lack of faith resulted in them wandering in the wilderness for 40 years and losing the chance to possess the land that God had promised them. 

The Pauline Author 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.