Dave Black has challenged me on my current belief about the authorship of Hebrews. I have believed for a while that it was Luke who was the author of the book. Yet it appears that the early church fathers – Origen believed that Paul was its author.
Truthfully I find much of Luke in the book of Hebrews, yet I also find much of Paul. So I am forced to reconsider my stance and modify it to being that Luke was the writer. He was the scribe. And it was Paul who was the author.
In many ways the book of Hebrews appears to be more of a sermon to a congregation then it is a letter to a church or a group. It lacks the standard salutation that the format of a letter normally has. Luke and Paul were long time travelling / ministry companions. I believe they would have had many long and deep discussions about God, Jesus, the cross and the church. There is no indication that they ever crossed words with each other and its likely that their individual theology and spiritual experiences where on the same par as each another.
Therefore in many ways Pauline theology is Luken and Luken theology is Pauline. We cannot and must not formulate a difference between them, for there is no real evidence to suggest they preached a different Gospel to each other. And therefore if Luke did write down a sermon that Paul preached, in many ways Luke has taken ownership of that sermon and written it down in his own style of writing and therefore the book of Hebrews becomes both Luken and Pauline in the essence of the one God, one spirit, one Christ, one saviour!
Just a few thoughts for now. 
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