What does Hebrews 3:5 mean?
Here, as in prior verses, the author of Hebrews supports the idea that Jesus is a "better" example than that of Moses. While Moses was created, Jesus is the Creator (Hebrews 3:3). While Moses was faithful, as a servant in God's house, Jesus is faithful as God's Son (Hebrews 3:6). Moses gave previews of what was to come, Jesus actually fulfilled those promises.Some of the aspects where Moses "testified" to the future include the tabernacle itself. Much of the tabernacle's construction was meant to be symbolic. The actions of the priests and high priests were also meant to foreshadow the ministry of Jesus.
This falls in line with the "big picture" message of this passage. For the Jewish Christian enduring persecution and doubt, this is both a comforting and challenging idea. If Moses is meant to be an example, but his actions point forward to Jesus, who is a greater example, and whose works are complete, it stands to reason that Jesus is the "better" One to follow. Prior to this verse, the focus has been on the importance of following the example of Christ.
In the next verses, this point will shift to point out a prior example of what happens when we fail to trust in God's promises: Israel's forty-year wandering in the desert.