Context? Let's take a look.
Verses 19-25 is an exhortation that begins with the writer calling out to brethren which means the writer considers the people he is writing to to be of the faith. He then continues the exhortation in verse 20, and 22 in the first person plural with the word US in connection to the way being consecrated and their hearts sprinkled from an evil conscience and bodies washed with pure water. If your hearts are sprinkled and our bodies washed we are saved.
Then again the writer in verse 23 councils in the 1st person plural that they, including himself should hold fast their profession of faith without wavering because of God's faithfulness. Then continuing in the first person plural He says in verses 24 and 25 that they, including himself should provoke unto love and good works as they see the day approaching.
These people the writer considers brothers in the consecrated way having their hearts sprinkled from and evil conscience and their bodies washed WHICH MEANS THESE PEOPLE INCLUDING THE WRITER ARE SANCTIFIED, SAVED.
They are to profess this faith without wavering. They are to provoke unto love and good works and our counseled not to forsake the assembling together as some do because they see the Day approaching. These people are likeminded believers with the writer. They are saved.
Then Continuing In Verse 26 with the word FOR. Which means what is about to be said is the reason for what was previously stated. The writer continues in the 1st person plural continuing to include himself in the admonition. How do we know? He uses the word we. Couple that with Verse 29 when he says that the sinning willfully individual was sanctified.
What is posted in this post are all objective facts. As is the fact that if we are sinning willfully, we whom are sanctified, having the way consecrated before us. Our bodies washed with pure water and our hearts sprinkled from an evil conscience. We the brethren, if we are sinning willfully after receiving the knowledge of the truth there remains no more sacrifice for sin. Only a certain fearful looking forward to judgement and fiery indignation which shall devour the adversary, those whom are sinning willfully.
And it would fail us not to mention after the admonition in verse 26-30 the writer starts in verse 32 with the word but and then begins to exhort those to whom he is speaking. Calling them illuminated.
You can't be sanctified, made holy and not be saved. Because you are not sanctified, made holy unless you have been saved.
Incidentally these sanctified illuminated individuals, brothers in the consecrated way having their hearts sprinkled from and evil conscience and their bodies washed are counseled to not cast away their confidence in verse 35 and within the same thought they are told that they are in need of patience, cheerful endurance. That after they done the will of God they MIGHT receive the promise. Which implies they MIGHT not receive the promise if they do not cheerfully endure.
Although the writer of Hebrews includes himself in this warning (if we sin willfully) note that he switches pronouns in
Hebrews 10:29 to "he" and at the end of the chapter (
Hebrews 10:39) the writer makes it clear that he considers himself a true believer by including himself in the "we" who do not "draw back to perdition." But
we are not of those who draw back to perdition, but
of those who believe to the saving of the soul. Those who
draw back to perdition do not believe to the saving of the soul and those who
believe to the saving of the soul do not draw back to perdition.
Once again, sanctified "set apart" in
Hebrews 10:29 is not the same as
"sanctified once for all" in
Hebrews 10:14. The one proves eternal (
Hebrews 10:14) and the other proves guilty of apostasy. (
Hebrews 10:29) The writer of Hebrews said
"sanctified through the offering of the body of Jesus Christ once for all"(
Hebrews 10:10) and in verse 14, we read,
"perfected for all time those who are sanctified." (
Hebrews 10:14) So even though the reference to "the blood of the covenant that sanctified him" in verse 29 "on the surface" appears to be referring to a genuine Christian, this overlooks the fact that the word translated "sanctified" (which is the verb form of the adjective "holy") which means "set apart," and doesn't always necessarily refer to salvation.
In
1 Corinthians 7:14, Paul uses the word to specifically refer to non-Christians who are "sanctified" or "set apart" by their believing spouse
and by this Paul does not mean that they are saved. A non-Christian can be "set apart" from other non-Christians without experiencing salvation as Paul explained. So the word "sanctified" means to be "set apart." If the word "sanctified" simply meant "saved" in every case, then you would have to say that the seventh day was saved (
Genesis 2:3), the tabernacle was saved (
Exodus 29:43), Moses saved the people after coming down off the mountain (
Exodus 19:14), the priests and the Levites saved themselves (
1 Chronicles 15:14), the Father saved the Son (
John 10:36), the Son saved Himself (
John 17:19) and many other things that do not line up with scripture.
Again, in verse 39, the writer of Hebrews sets up the
CONTRAST that makes it clear to me that he was referring to unbelievers, not saved people: But
WE are not of those who draw back to perdition, but
OF THOSE who believe to the saving of the soul.
So after considering the
CONTEXT, it seems most likely that "he was sanctified" should be understood in the sense of someone who had been "set apart" or identified as an active participant in the Hebrew Christian community of believers, but then later renounces his identification with these other believers, by rejecting the "knowledge of the truth" that he had received, and trampling under foot the work and the person of Christ himself. This gives evidence that his identification with these Hebrew Christians was only superficial and that he was not a genuine believer.
Throughout the book of Hebrews, we see "nominal" Christians mixed in with genuine Christians, like in
Hebrews 4:1-2. For indeed
the gospel was preached to US as well as to THEM; but the word which they heard did not profit THEM, not being mixed with faith in those who heard it. For
WE who have believed do enter that rest, as He has said: "So I swore in My wrath, 'They shall not enter My rest," although the works were finished from the foundation of the world. Obviously, not all of these Hebrews were genuine believers. Notice that verses 2-3 makes a
distinction between US who have BELIEVED and do enter that rest and THEM who heard the word but did not mix faith with what they heard and will not enter that rest because of UNBELIEF.
So it's not hard to find "nominal" Christians mixed in with genuine Christians in the book of Hebrews and throughout scripture and in various churches today and on various Christian forum sites. You seem to overlook this fact.