Hebrews 1:1,2 - He has spoken to us by His Son.

1:1

There are none of the usual greetings or prayers that have come to expect from Paul’s letters, not even any indication of to whom the letter was sent. Instead we dive straight into the meat of the letter, which is how everything in the past was leading up to Jesus Christ. God had spoken to Israel in many and various ways and at various times through the prophets. The writer will in no way diminish these prophets, but will demonstrate how Jesus is the fulfilment of the prophets. This is consistent with what Peter says 1 Pet 1:18-20.

1:2

Now God had spoken to them through His Son. The same pattern is spoken of in the parable of tenants (Matt 21:33-46). The Son is infinitely greater than the prophets. He has been appointed as heir of all things. This means that everything hinges upon Him, the future will all be based around Him. So the role of the Son extends forward into eternity, it also extends backwards into eternity. For it was through Him that God made the universe.