Who was the book of Hebrews written to?
The book of Hebrews was written primarily, though not exclusively, to Jewish believers. Paul is identified as writing it, and he used many Old Testament contacts and experiences to make his points, which fits that primary audience of Jewish believers.
Les teaches that when Paul wrote the book of Hebrews, he was writing primarily, not exclusively, to Jewish believers. Because of that audience, Paul draws heavily on Old Testament contacts and experiences to make his point. Les then points to Hebrews chapter 3, verse 7, where Paul quotes from Psalms about hearing the Holy Spirit's voice, not hardening hearts as in the provocation and the day of temptation in the wilderness. Les connects this to the forty-year wilderness experience that followed their rejection of going in at Kadesh Barnea, and to the generation with whom God was grieved.