What does Hebrews 10:26 mean? I thought the knowledge of the truth was knowing that we are shaped in iniquity, sinners through and through, and destined to die that way. However, Jesus death which was the sacrifice that paid for our sins, wiped the slate clean, And now we are no longer slaves to sin and the penalty of death. And that sacrifice is eternal, we just have to accept it, And put our faith in him.


  Hebrews 10:26  For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, KJV


So if we willfully sin after being saved will it be covered by Jesus death and resurrection?
In answer to your question;

(note) all Scripture is quoted from the King James translation.

The key word in:


  Hebrews 10:26  For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, 


is the word truth.


  John 14:6  Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me. 


If we break down Hebrews perhaps we can understand it better.

(if we sin willfully.) the first thing we have to know is what sin is Paul referring to. We get our first clue in:


  Hebrews 10:10  By the which will we are sanctified through the offering of the body of Jesus Christ once for all. 


Our second clue comes in:


  Hebrews 10:14  For by one offering he hath perfected for ever them that are sanctified. 


and third:


  Hebrews 10:18  Now where remission of these is, there is no more offering for sin. 


So this is telling us that once your sins are forgiven by Jesus death and resurrection, it cannot be done a second time.

Now notice that it says * knowledge*.

So the sin referenced here  refers to Knowing Jesus and the willful part has to do with denying that Jesus is the way to Salvation.