Hebrews, with its insistence on the preeminence of Christ, here furthers the argument with a comparison of Christ and Moses.  The argument here is a simple development of what has already been established in the letter's line of argumentation.  Jesus is worthy of imitation, specifically in his demonstration of faithfulness.  He is worthy of even greater honor that Moses, because while Moses was faithful in his role as a servant in God's house, Jesus is not only a servant, but the son who rules over the house.  In the metaphor, the house represents God's faithful people.  The writer then includes himself and the reader as part of the house, with the condition "if we hold on to our courage and the hope of which we boast." 

The thought here really is similar to the note at the beginning of chapter 2, "so that we will not drift away".  Here though, the author picks up the thread and develops it more substantially.  Holding on to our courage, being sure that we don't drift away, forms the core rhetorical objective of the letter.  The author's purpose throughout is to encourage the readers, to support them against the possibility of drifting away from the faith.  In 2:7 the letter turns to address that theme more fully.

Some thoughts that pop out to me in this latter section of the chapter:

1. Perseverance (which is behavioral) is tied to the ideas of belief and faith in this section.  An unbelieving heart is one that turns away.  In 18-19, disobedience is tied to unbelief.  So there is a connection between the behavioral and the cognitive here.

2. Communal encouragement is a weapon against this type of disobedience.  By strengthening each other we become more resilient.  We are less likely to be deceived by sin, hardened by it.  The implication is that part of what happens when people abandon their faith is that they become discouraged, and discouragement opens the door for deceit.  I think this bears true to my experience as a witness.  I think discouragement is more deadly than ignorance in matters of faith, and yet our primary modes of operation seem to strike at education rather than encouragement.  Not that I believe education, the formation of better understandings, to be wasteful, but the role of specific strategic encouragement may be understated.

3.  It strikes me that belief is a process, involving faithfulness over many years.  The jury is out on whether we truly believe, until it has been seen whether or not we will remain faithful.  Coming to faith is one thing, but remaining faithful is another, and one that is absolutely critical if we are to enter the promised land.