The Letter to the Hebrews (sometimes called The Book of Hebrews) is attributed to the Apostle Paul, although some doubt that he wrote it,
Paul never quite turned loose of his ministry to the Jews (although he was called an apostle to the nations). I believe the letter to the Hebrews was written by Shaul b'Tarshish in such a way as to disguise his authorship because by that time his name was already sullied in Jewish circles.
Hebrews 1
1 In the past God spoke to our forefathers through the prophets at many times and in various ways,
2 but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe.
3 The Son is the radiance of Gods glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven.
4 So he became as much superior to the angels as the name he has inherited is superior to theirs.
5 For to which of the angels did God ever say, You are my Son; today I have become your Father? Or again, I will be his Father, and he will be my Son?
6 And again, when God brings his firstborn into the world, he says, Let all Gods angels worship him.
7 In speaking of the angels he says, He makes his angels winds, his servants flames of fire.
8 But about the Son he says, Your throne, O God, will last for ever and ever, and righteousness will be the scepter of your kingdom.
9 You have loved righteousness and hated wickedness; therefore God, your God, has set you above your companions by anointing you with the oil of joy.
10 He also says, In the beginning, O Lord, you laid the foundations of the earth, and the heavens are the work of your hands.
11 They will perish, but you remain; they will all wear out like a garment.
12 You will roll them up like a robe; like a garment they will be changed. But you remain the same, and your years will never end.
13 To which of the angels did God ever say, Sit at my right hand until I make your enemies a footstool for your feet?
14 Are not all angels ministering spirits sent to serve those who will inherit salvation?
This calls into question your interpretation of whom he wrote the letter to. Why would he disguise his writing if they were believing Jews already?
but it nonetheless is striking to me, a Jew, because it was written to converts from Judaism to Christianity, Messianic Jews if you will,
No I won't. This was a letter written by a scholar of Torah to people who knew Torah to convince them about the superior Torah the Higher Torah which puts the Mosaic Torah to proper use (the lesser driving the people to the greater).
Galatians 3:24-25
24 Wherefore the law (Torah) was our schoolmaster to bring us unto Christ, that we might be justified by faith.
25 But after that faith is come, we are no longer under a schoolmaster.
This is not antinomianism as some have accused (Romans 3:8)...
1 Corinthians 9:19-21
19 Though I am free and belong to no man, I make myself a slave to everyone, to win as many as possible.
20 To the Jews I became like a Jew, to win the Jews. To those under the law I became like one under the law (
though I myself am not under the law {Torah}), so as to win those under the law.
21 To those not having the law I became like one not having the law (
though I am not free from Gods law {Torah} but am under Christs law {Torah}), so as to win those not having the law.
The book of Hebrews is as a commentary on:
Jeremiah 31:31-34
31 The time is coming, declares the LORD, when I will make a new covenant with the house of Israel and with the house of Judah.
32 It will not be like the covenant I made with their forefathers when I took them by the hand to lead them out of Egypt, because they broke my covenant, though I was a husband to them, declares the LORD.
33 This is the covenant I will make with the house of Israel after that time, declares the LORD. I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people.
34 No longer will a man teach his neighbor, or a man his brother, saying, Know the LORD, because they will all know me, from the least of them to the greatest, declares the LORD. For I will forgive their wickedness and will remember their sins no more.
Written to Jews to consider / further their consideration of entering into the New Covenant.
and so my question is that many Christians will state that the "New Testament" is only a fulfillment of the "Old Testament" and yet the Gospels clearly state that the entire "old law" is made void by Jesus Christ:
"But he (Jesus) is worthy of more "glory" than Moses, as the founder of a house has more "honor" than the house itself." - Hebrews 3:3
"For if that first covenant had been faultless, no place would have been sought for a second one. But he finds fault with them and says:
~snip~
As I showed you with Galatians 3:24-25 and 1 Corinthians 9:19-21 the Mosaic Law was to drive men to the Law of God / Law of Christ through the futility of trying to fulfill the Mosaic Law. By seeking mercy rather than justice, God grants us the righteousness of Messiah (which fulfills the Mosaic Law). The Mosaic Law still stands to condemn the unbelievers for their unbelief.
John 5:43-47
43 I have come in my Fathers name, and you do not accept me; but if someone else comes in his own name, you will accept him.
44 How can you believe if you accept praise from one another, yet make no effort to obtain the praise that comes from the only God?
45
But do not think I will accuse you before the Father. Your accuser is Moses, on whom your hopes are set.
46 If you believed Moses, you would believe me, for he wrote about me.
47 But since you do not believe what he wrote, how are you going to believe what I say?
Deuteronomy 18:15-19
15 The LORD your God will raise up for you a prophet like me {Covenant Maker} from among your own brothers.
You must listen to him.
16 For this is what you asked of the LORD your God at Horeb on the day of the assembly when you said, Let us not hear the voice of the LORD our God nor see this great fire anymore, or we will die.
17 The LORD said to me: What they say is good.
18 I will raise up for them a prophet like you {Covenant Maker} from among their brothers; I will put my words in his mouth, and he will tell them everything I command him.
19
If anyone does not listen to my words that the prophet speaks in my name, I myself will call him to account.
John 3:16-18
16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.
17 For God did not send his Son into the world to condemn the world, but to save the world through him.
18 Whoever believes in him is not condemned, but whoever does not believe stands condemned
already because he has not believed in the name of Gods one and only Son.