Hebrews 1:1-3 (NIV)
In the past God spoke to our forefathers through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe. The Son is the radiance of God's glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven.
Prophets speak for God, but Jesus is the actual Word of God as John 1:1 says. This is the foundation upon which all of Christianity rests--that God has spoken to us. If God did not speak, then we have no religion and no savior. But He did speak; we have His words and they tell us who He is and what He is like and they tell us how we can know Him. And the answer to all these is Jesus Christ. That is the point of this book of Hebrews.
Jesus has had a number of jobs to do. First, He made the universe and everything in it. Second, he appeared numerous times to men of the Old Testament. Third, He came to this earth to allows to "see" the Father because he is the perfect and visible image of the invisible God. Fourth, Jesus not only made the universe but he currently maintains it as part of his current intercessory ministry. Fifth and best of all, Jesus job was to become a satisfaction for our sin debt owed to God. This verse speaks of it as a purification or a cleansing of our sins. Lastly, Jesus is now seated at the right hand of the throne of majesty in heaven.
Thus begins the prologue and the superlative affirmation of the superiority of Jesus Christ in the magnificent book of Hebrews.