I asked you first. What are YOUR thoughts along this line and why? Please comment on the quotes I provided in my post to you earlier that clearly stated that ALL their iniquity was forgiven by their bloody placement upon the goat's head, symbolic of their sins, to be sent out into other regions and the wilderness? I'd really like to hear your thoughts on that first given that I asked you first.
My view is that Christ was in the beginning with God, and is the redeemer of all the faithful in all times.
Job was a contemporary of Abraham, and when he says: "For I know that my redeemer liveth, and that he shall stand at the latter day upon the earth" (Job 18:25), he speaks of Jesus.
No man can see God and live, yet Jacob was able to wrestle with God and prevail through Jesus, hence the original meaning of the name "Israel".
Regarding the OT saints, Hebrews 11 explains how it all works.
On your Acts 21 passage, it seems the accusation against Paul was (V.21) "that thou teachest all the Jews which are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs".
It seems that he really did that, and his motivation for purifying himself with the Jews was not because it was his general practice, but because he was at liberty to do so.
He was just trying to stay alive.
Notice that when he gives his defense in the next chapter he uses his Roman citizenship in much the same way.
Peter, who you mention was an apostle to the Jews, was not that exclusively.
In Acts 10 we read of him ministering to Cornelius, the first Gentile convert.
Notice that in his vision he was instructed to eat the unclean animals.
If I was to accept a view that Jewish Christians are required by God to continue under the law of Moses, my belief would have to harmonize with the whole of scripture, otherwise I would consider that I have made a mistake.
The Holy Spirit does not contradict itself, and Moses himself prophesied that the conditional Mosaic covenant would be broken.
Deuteronomy 31:16 And the Lord said unto Moses, Behold, thou shalt sleep with thy fathers; and this people will rise up, and go a whoring after the gods of the strangers of the land, whither they go to be among them, and will forsake me, and break my covenant which I have made with them.
The Mosaic covenant was given to the nation of Israel only, so if we read anything about it's abrogation anywhere in the NT, we are reading concerning the Jews.
None the less, to avoid complication I use the book of Hebrews:
Hebrews 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.