The book of Hebrews was written to people who knew the Old Testament well, who had followed its teachings for generations. God had been creating a picture of Jesus for centuries so He would be recognized when He came to earth. But people then, and even still today, clung to the old traditions and ways of life. They wanted to follow the shadow rather than the reality.
But as we look carefully at the pictures God had painted of Jesus in the perfect lamb to be sacrificed at Passover, or the silver of redemption which formed the foundation for the Tabernacle, or Moses the beloved leader who led the people to freedom — in all these pictures we find beautiful details of Jesus which we might overlook if it were not for the enduring picture. In Jesus, in His reality, however, we find He is sufficient for all our needs in our life both now and for eternity. See the details in the picture, but seek the reality in your relationship with the living Jesus.