I'm venturing to guest most of them are messianics. I understand why they say that.
The 10 commandments are defined specifically in Exodus 20. They were written down by the finger of God on Mount Sinai on 2 stone tablets.
The 10 commandments are eternal laws that actually reflect Christ's character. Jesus summerized into 2 parts: 1-4 are our duty to God: love God; 5-10 are our duty to man: love your fellowman.
The 10 commandments were given long before Mount Sinai.
1 John 3:4 ...for sin is the transgression of the law.
Romans 3:20 ...for the law is the knowledge of sin...
1 John 3:8 He that committeth sin is of the devil; for the devil sinneth from the beginning.
If the devil sinned from the beginning, then the 10 commandments must already been in effect from the beginning. Indeed, because they are the transcript of Christ' character which is eternal.
The bible is explicit about the 10 commandments' existance before mount Sinai, but we can see evidence of them:
The sabbath commandment was given after creation: God rested on the 7th and made it holy.
Cain sinned when murdered Abel.
When Abraham sojourned the land of Gerar, Abimelech the king of Gerar took his wife Sarah. God appeared to Abimelech in a dream to warn him not to sin:
Gen 20:6 And God said unto him in a dream, Yea, I know that thou didst this in the integrity of thy heart; for I also withheld thee from sinning against me: therefore suffered I thee not to touch her.
And in Gen 35, the strange gods were put away from the house of Jacob.
So the 10 commandments weren't spelled explicitly, the principles were already made clear prior to mount Sinai.
After the children of Israel came out of Egypt, they didn't speak the paleo-Hebrew. They had forgotten all the ways of God. That was one of the reasons they couldn't enter into the promise at once. They had to rid themselves of all the paganism they adopted from the Egyptians. So much so, that right at the foot the Mount Sinai when Moses was on the Mount to meet God, the children of Israel committed all sorts of sins. Moses expanded on the 10 commandments to close all the possible 'loop holes'.
That's like you have the constitution, the upper case law. But then state and local laws were added. Even the traffic laws later, to prevent people looking for loop holes.
Paul in Galatians 3 talked the law of Moses was added 430 years after the promise was made to Abraham because of the transgression. Paul said the law of Moses had met its purpose when Jesus came and we are no longer under the law of Moses. This was also confirmed by the Council of Jerusalem in Acts 15.
So the messianics today contend that there weren't 10 commandments but 613 commandments because they are still zealous for the law of Moses.
And those that don't keep the sabbath say Jesus gave two commandments only: love God and love your neighbor.
But Jesus said if you love me, keep my commandments as I have kept my father's commandments.
Paul said in Hebrews 4 there remains a 7th day rest (shabbat) for the people of God.
And Isaiah 66 says all the redeemed will continue to worship God on Sabbath.
I hope this is clear.
About the 1844 issue, someone had asked a similiar quesition. I'm going to refer you to the earlier discussions we've had.
http://www.christianforums.com/t2564...judgement.html
http://www.christianforums.com/t3883981-resources-for-the-sanctuary.html
http://www.christianforums.com/t3039271-the-sanctuary-study.html
I know they are lengthy. But this is a complex topic. So take your time to study them and have a deep understanding of the sanctuary.