So far, the Writer is making an overarching superlative-style point. Chapter 1: Jesus is better than angels. Chapter 2: Jesus is better than humans. Chapter 3: Jesus is better than Moses. Now, there's a little more to it than that, but I'm looking at the big picture for a second. The Writer wants to be sure we know: nobody trumps Jesus. Not the senior angel, the greatest human, the most legendary figure in Jewish history. Nobody.
In chapter 3, we are admonished from the very first words to focus on Jesus Christ, not any person, not even Moses himself. This would have been a pretty provocative statement to make to a Jewish audience, since Moses was the person who led the single most defining event in Jewish history - the Exodus from Egypt (you can read about this in the book that bears that event's name - the second book of the Bible). Moses encountered God in a very unusual way, was chosen by God, spoke on behalf of God, performed miracles to display the power of God, and recorded the Law of God. Nobody - and I mean NOBODY - had the kind of memorial power that Moses did. in a way that is far beyond what most of us can comprehend, the Jewish people revered him. Think George Washington (to all of us who are Americans) or Henry Ford (for the innovators) or Michealangelo (for artists) or Beetoven (for the musicians). Now, multiply the feelings that person's name invoke in you by a thousand. Now you're somewhere in the vicinity of how the Jews felt about Moses.
For someone to be superior to Moses would be...blasphemy. unspeakable. unthinkable.
But Jesus is better than Moses. He's higher than and superior to Moses. The Writer says, 'hey, who's greater: the house or the builder of the house?" And he answers his own question: the builder, of course. Moses is a created being - a GREAT created being, but a created being nevertheless. Jesus is the CREATOR.
Now, there is a curious part of Hebrews 3 that most leaders in the Church today want to ignore. I admit that I want to ignore it, too, because it messes with my theology of salvation (what it means to be 'saved' and assured of heaven). I believe, based on other texts, that if you sincerely give your life to Jesus, ask for forgiveness, and dedicate yourself completely to him, you are saved, forgiven of your sins, and guaranteed a place in heaven when you die. But the Writer opens the door to the notion that salvation can be 'lost'. 3:14 "We have come to share in Christ if we hold firmly till the end the confidence we had at first." And v.6 "...And we are his house, if we hold on to our courage and the hope of which we boast." Personally, I don't like these 'if' statements. But it doesn't really matter what I like, what matters is truth. And this is a link in our pursuit of truth.
Honestly, I'm not sure what to do with these texts, but they require more research than we can do here. One application is easy, though: Stay close to Jesus Christ and hold firmly to the commitment you made to Him! Ask God, "What does it mean that I promised you my life? How can I live out that promise more fully right now?"