Yes, and God's revelation is progressive. Under the old covenant He used types and shadow to point forward to the Substance, Jesus Christ. He no longer regards those older types and symbols since the thing to which they all pointed has arrived and been revealed to the world in the flesh.
If the New Covenant basically erases the OT, then was God just messing with the Hebrews, teaching them poppycock and laughing at them from on high?
I'm not sure trht you mean by "erases". No one said the NT "erases" the OT. But obviously there have been significant modifications, esp. in the area of the cultic laws that were peculiar to Israel as a national entity under the tutelage of priesthood according to the order of Aaron.
But that priesthood and those rules no longer exist today. The sacrifices have been abolished once and for all because the substance to which he sacrifices pointed, Jesus Christ, has appeared.
All the feast days were in inextricably tied to the sacrificial system. Every feast -- in order to be faithfully observed -- had to have an animal killed and the blood sprinkled about.
No one has been able to point to a single passage in the Bible which teaches the church composed of Jews and gentiles how to observe Rosh Hashanah or any other annual feast day without an animal sacrifice.
Rather, what we have today are mere traditions invented by folks to explain how they think these things ought to be observed. But it just a human invention.
The volume of information that parallels the OT with Jesus with the Second Advent is huge.
Perhaps, but perhaps also it it merely the presuppositions that one brings to the table that makes it seem huge. I'm not convinced to the point that I would try to keep cultic Jewish feast days as a pointer to the Second Coming.
Where does the sin of presumption --the sin of Nadab and Abihu -- come into play?
If faith does not lead to obedience, what good is it?
Yes, but obedience to what? Decayed commands that were a part of the older system specifically tied to Israel in the land?
Which ones do you choose to obey, and which do you choose to ignore? Do you shave around the sides of your head? Do you wear clothing of mixed materials? Do you take your medical problems to a priest? Do you pay all your employees every day, or do you expect to be paid by your employer every day? If you find a dead mouse a your basement do you considered yourself ritually unclean for a day if you touch it? Or if you touch a person with a "discharge"?
Which of the 613 so-called mitzvot to you follow and which do you ignore?
I don't know about you, but this verse scares the crap out of me.
Are you saying that anyone who does not follow your traditions and observe a blood-less, temple-less, priest-less Rosh Hashanah today because they can't find the authority to do so in the Word of God is sinning against almighty God? That's a rather bold position, and one certainly in need of much biblical support.
The new moon feasts and sabbath are kept in the millenium.