Your religion is showing again..
The whole book of Hebrews was written to the Hebrews...in their synagogues there were believers and unbelievers..the author od Hebrews is showing through their own religious system about their need to come to Christ.
All sin is willful and if your interpretation is right then all of us are in deep trouble because we all sin everyday and it is willful..lol
The only sin talked about in the book of Hebrews is the sin of unbelief in chapter 3 and 4..then he goes on to talk about the High Priest..the sacrifices of bulls and goats..etc...
The "willful sin" is rejecting Jesus as their Messiah and relying on the temple sacrifices for their salvation. Unbelief is disobedience..
I know you need these verses to say that we can lose our salvation because that is what you believe..and as I have said before..you can believe whatever you want...I am just giving people a grace-based view to read and they can make their own minds up with the Holy Spirit within them....