The author continues to show the superiority of Christ in all things. In vs. 1-6 he shows that Jesus Christ is superior to Moses. Moses was faithful to his role as a servant in the house of God. Jesus was faithful in his role as Son of God. The son outranks a servant, therefore Jesus Christ is greater than Moses. To carry the point further, Jesus, as son of God, is not only the heir in the house he is the builder.
The chapter concludes with an extended admonition against unbelief. Today -- do not harden your hearts. Today -- when you hear the voice of God believe and receive. We are told (13) to exhort one another daily to believe and live the faith and calling to which we were called.
Exhortation is essential to the Christian journey. What would any of us do without the encouragement and support of the Christian community. We all have days of darkness and struggle -- it is the exhortation of fellow Christ followers that helps to pull us through. Simply put: we need each other.