Now, I'm all for proceding in the Spirit, but let's get one matter out of the way first: Is it in fact your contention that someone saying that we should keep the Feasts is legalism, but someone saying that we must not keep the Feasts is not legalism? That seems to be a curious double-standard to me.
What I have always said is that keeping the feasts/dietary laws/circumcision/etc is a matter of adiaphora as far as individual believers are concerned. I would say the same of people who wish to exchange gifts on December 25 and call it "Christmas".
My objection is when folks bring these things into the church as normative worship practices for a congregation of baptized believers (Jews/gentiles/both, doesn't matter). In my understanding of Scripture, under the new covenant God could care less if we have a roast pork dinner at a church gathering, where clothing of mixed material, cut or beards a certain way, or do not remember the "passover" or "yom kippur". In fact, what would be offensive to God is if we insist on doing these things which are personally adiaphora in the context of corporate worship among other brothers and sisters who believe they have been set free from these thing in Christ. To force adiaphora on the church would be denying them their liberty since they do not constitute the "commands of Christ".
So, far from being "legalism" in any true sense of the word, the objection is to the sense of spiritual superiority that comes from "messianic judaism" v. "gentile christianity" based on the idea that keeping what were admittedly laws pertaining to Israel as a nation in a particular time and place that are somehow normative for the universal church under the new covenant.
Or, to put it another way, if you believe that for me (or anyone else who calls himself a Christian) to keep these laws or not keep these laws is a matter of absolutely moral indifference (adiaphora), then we are OK. But, if you insist that I will be better off spiritually and truly pleasing to God by devoting myself to keeping these things in as scrupulous a manner as can be defined in this day and age, then I call that "legalism" and a judaizing of the church.
So that is where I stand on the ceremonials.
The weekly sabbath is a different issue in my mind since it involves the moral law (the 4th of the "Ten Words") and is not the strictly ceremonial. I have a difficult time thinking that God has left the day of the week for worship by His body a matter of adiaphora. I could be wrong, but it doesn't seem to be the case. So we are left with trying to understand based on all that is given to us in the Bible what was God's intention for weekly sabbath worship under the terms of the new covenant within the universal body of Christ. Obviously, we disagree on the proper interpretation of certain Scripture passages. You think I'm wrong and I think you're wrong. Sometimes it escalates to outright name calling; "legalist" v. "judaizer".
I'm not sure if this question is useful, but let me ask anyway. When we talk about the fact that "Christ died for our sins" (1 Cor. 15:3), I assume you believe that means that if a person were an actual murderer, then Christ died for the particular act of murder in that person's background. Would it also be your belief that for a Christian from a gentile background that means that Christ died for the sin of eating swine flesh or not properly worshipping on the "passover"?
Yes, I know where my clothes are that I need to wear.
Although not specifically addressed to me, I would like to respond to this question.
Christ died for every sin that we can commit. Deliberately disobeying God breaks at least two commandments:
Exo 20:3 Thou shalt have no other gods before me.
In the case of eating unclean animals, Christianity has instituted it's own ideas about what to eat as opposed to God's wishes. They have put their religious beliefs ahead of God...they have another god before God. Same thing with not observing Passover or any other holy day.
It also violates that 5th commandment:
Exo 20:12 Honor thy father and thy mother: that thy days may be long upon the land which the LORD thy God giveth thee.
God, our father, is not being honored when he specifically tells us, his children, to not eat the flesh of certain animals...or when we disregard his instructions on the holy days.
As a father, God does things for reasons we might not understand for a while. We obey on faith. I know that there are profound spiritual rewards for obeying God on these points, but I had to step out on faith and do them without knowing exactly what those rewards might be.
It's like a father telling a little kid not to play in the road. The kid doesn't have a clue what the actual consequences of disobedience might be, but the father knows it may end up killing the kid. The kid can rationalize all day that the traffic is light, that the drivers will see him and stop in time, the speed limit is low, that he's fast enough to get out of the road, etc., etc. ...and may consider his fathers rules to be restrictive and stupid. But the father has seen plenty in his lifetime and KNOWS what the best course of action is.
It's the same with God. He's been around longer than forever. He knows the dangers to humans in the world. He knows how are bodies are designed and what the best and safest fuel for them is. He knows how to build our spiritual character. When we disregard his instructions, there are always consequences.
1) What is the Biblical definition of sin, as you understand it?
2) You keep objecting against keeping the Appointed Times of the Lord becoming the "normative worship practices for a congregation of baptized believers." What do you mean by that exactly? Are you objecting to the very existence of congregations that choose to observe the Appointed Times of the Lord in lieu of Sunday, Christmas, etc.?
3) If you object to a perceived "spiritual superiority" among Messianics, then should my perception of a superiority complex among Calvinists cause me to a priori reject your tenants as you reject ours?
And to answer your question:
Would it also be your belief that for a Christian from a gentile background that means that Christ died for the sin of eating swine flesh or not properly worshipping on the "passover"?
I have already stated my ambivalence over whether eating pork is a sin for a Gentile believer since there are (to my mind) caveats for Gentiles built into the Torah itself, so my answer to the first part would be, "If eating pork is indeed a sin for a Gentile believer, then yes."
My answer to the second question is also yes, with the caveat that I have said nothing about worshipping "properly" outside of keeping the specific commandments associated with the Passover. I believe that within the framework of the written Torah (and by extension, all Scripture) there is plenty of room for individual expressions of worship and cultural traditions. Even though I observe these Feasts from within a Jewish cultural tradition, I also recognize the need for modification to reflect our New Covenant belief; e.g., the Passover is no longer solely about the Exodus from Egypt, but also our Exodus from sin in our Lamb Yeshua, and the Seder needs to express that.
As for why I would consider such things sins, I'll explain that in more detail when you answer my question #1, since my answer will be tailored according to yours. Fair enough?