I have never disputed with you that sin is a breaking of God's Law. That is not under debate. What is up for debate here is what God's Law is for us today versus what God's Law was before Christ. The two are very different.
Melchizedek was not High Priest. He was just a priest to God, and also the king of Salem. Jesus is like him in that Jesus is also both King and priest, but Jesus is High Priest, and King of Kings.
Again, I have never disputed that the Laws of God did not exist before the Law was given at Mt Sinai. And the laws against murder, adultery, lust, (1, 2, 3, 5, 6, 7, 8, 9, & 10 of the ten commandments) are all restated as being still part of the NT just as they were in the OT. But keeping the sabbath is not listed among the laws we must keep under the NT.
Baptism also initiates the continual cleansing that washes away all future sins as well.
Again, this is not under debate. We must keep the laws of God as they pertain to us today. But the keeping of the sabbath does not pertain to us today.
Going to church on Sunday, the pagan holidays of Christmas and Easter, praying to the Virgin Mary, I could go on and on. And most so-called Christians know these rituals have nothing to do with Jesus and the Bible, but a lot of work get put into them. But the Sabbath day is all through out the Bible and you going to trick yourself in believing the Sabbath day is done away with.
Jesus made it clear that the seventh day was made for mankind. (Mark 2:27-28) (v.27) And he said unto them,
The Sabbath was made for man, and not man for the Sabbath: Do we understand that, the Sabbath was made for us, not us for the Sabbath. (v.28)
Therefore the Son of man is Lord also of the Sabbath. The Son of man (Jesus) is the Lord God of the seventh day Sabbath (Saturday).
Paul say in (1 Tim.4: 1) Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith,
giving heed to seducing spirits, and doctrines of devils; The first day of the week, as the Sabbath day, is the doctrine of the devil. Satan is always trying to mimic God. So if it is not of God then it is of Satan.
So if the seventh day Sabbath (Saturday) is a sign between God and His people. Then the first day (Sunday) is a sign between somebody and his people. You can’t have it both ways you are either in or out. Paul says in 2 Corinthians 11: 4
For if he that cometh preacheth another Jesus, whom we have not preached,
or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him.
Also Paul say in (1 Cor.10:20-22) (v.20) “
and I would not that ye should have fellowship with devils”. (v.21)
Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord's table, and of the table of devils. (v.22)
Do we provoke the Lord to jealousy? are we stronger than he?
Not true. All of the OT was removed. The law of circumcision, which dates back to Abraham (400 years before the Law was given on Mt Sinai (Gen 17, Gal 5:2-6), is no longer relevant under the NT. The law of meat restrictions which was first given at Mt Sinai (Lev 11, Deut 14) is no longer relevant under the NT (Mark 7:18-19, Acts 10:9-16). The law of keeping the sabbath is no longer relevant under the NT (Col 2:16-17, Rom 14:5-9). The law restricting the priesthood to the Levites is no longer relevant under the NT (Heb 7:12).
Yes, walk in the commandments of God that are relevant to your time. Abraham walked in the commandments of God that were relevant to him. He was not circumcised until he was a very old man (not when he was 8 days old like those under the Law of Moses had to be). He could eat any meat that he pleased, because there were no dietary restrictions in his time. Melchizedek was priest to God, because there was no law restricting the priesthood to the Levites. And there was no sabbath keeping in Abraham's time. But during the time of the Law of Moses, these things changed. Now we are under only the NT laws. We are not subject to the laws given in the OT in any way, for it has been fulfilled, completed, swept away, and is no longer relevant to anyone living in the NT era.