Ah, I begin to see the problem:
Where do you get the idea that the Law can be separated into parts we obey and parts we don't? All scripture as scripture itself tells us is useful for instruction and reproof. But the Law is whole. You can't divide it into pieces. Go back and read Exodus again. God gave the Law as a whole identity for the children of Israel. The ENTIRE Law, ceremonial, moral, civil, was fulfilled by Christ. No one part of the Law is any more important than any other part of the law and breaking any one part of the Law results in having broken the entire thing. As James says:
Jas 2:10 For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.
You can't seperate out the 10 Commandments from the rest and say "these must still be obeyed or your salvation isn't complete". You can't even seperate out those 10 and say these are the most important, because Christ Himself said that that the two greatest commandments were to "love your God and love thy neighbor as thyself" and on those two hang the entire law and the words of the prophets.
The Law served its purpose in pointing man toward Christ, but once Christ was come, the Law now only serves as a curse.
Galations puts it this way:
Gal 3:10 For as many as are of the works of the law are under a curse: for it is written, Cursed is every one who continueth not in all things that are written in the book of the law, to do them.
Gal 3:11 Now that no man is justified by the law before God, is evident: for, The righteous shall live by faith;
Gal 3:12 and the law is not of faith; but, He that doeth them shall live in them.
Gal 3:13 Christ redeemed us from the curse of the law, having become a curse for us;
.
.
.
Gal 3:24 So that the law is become our tutor to bring us unto Christ, that we might be justified by faith.
Gal 3:25 But now that faith is come, we are no longer under a tutor.
Gal 3:26 For ye are all sons of God, through faith, in Christ Jesus.
I'm justified by faith. Keeping the Law doesn't make me anymore justified. That task has been accomplished by Christ. It's done.
We are saved by Jesus keeping the law that we broke, but we are not lawless.
Because the 10 commandments were added to mosaic law,does mot mean that they did not exist before or after moses......see the post to webdog,or better still, let me repost for you
Chapter 19: Of the Law of God
1._____ God gave to Adam a law of universal obedience written in his heart, and a particular precept of not eating the fruit of the tree of knowledge of good and evil; by which he bound him and all his posterity to personal, entire, exact, and perpetual obedience; promised life upon the fulfilling, and threatened death upon the breach of it, and endued him with power and ability to keep it.
( Genesis 1:27; Ecclesiastes 7:29; Romans 10:5; Galatians 3:10, 12 )
2._____ The same law that was first written in the heart of man continued to be a perfect rule of righteousness after the fall, and was delivered by God upon Mount Sinai, in ten commandments, and written in two tables, the four first containing our duty towards God, and the other six, our duty to man.
( Romans 2:14, 15; Deuteronomy 10:4 )
3._____ Besides this law, commonly called moral, God was pleased to give to the people of Israel ceremonial laws, containing several typical ordinances, partly of worship, prefiguring Christ, his graces, actions, sufferings, and benefits; and partly holding forth divers instructions of moral duties, all which ceremonial laws being appointed only to the time of reformation, are, by Jesus Christ the true Messiah and only law-giver, who was furnished with power from the Father for that end abrogated and taken away.
( Hebrews 10:1; Colossians 2:17; 1 Corinthians 5:7; Colossians 2:14, 16, 17; Ephesians 2:14, 16 )
4._____ To them also he gave sundry judicial laws, which expired together with the state of that people, not obliging any now by virtue of that institution; their general equity only being of moral use.
( 1 Corinthians 9:8-10 )
5._____ The moral law doth for ever bind all, as well justified persons as others, to the obedience thereof, and that not only in regard of the matter contained in it, but also in respect of the authority of God the Creator, who gave it; neither doth Christ in the Gospel any way dissolve, but much strengthen this obligation.
( Romans 13:8-10; James 2:8, 10-12; James 2:10, 11; Matthew 5:17-19; Romans 3:31 )
6._____ Although true believers be not under the law as a covenant of works, to be thereby justified or condemned, yet it is of great use to them as well as to others, in that as a rule of life, informing them of the will of God and their duty, it directs and binds them to walk accordingly; discovering also the sinful pollutions of their natures, hearts, and lives, so as examining themselves thereby, they may come to further conviction of, humiliation for, and hatred against, sin; together with a clearer sight of the need they have of Christ and the perfection of his obedience; it is likewise of use to the regenerate to restrain their corruptions, in that it forbids sin; and the threatenings of it serve to shew what even their sins deserve, and what afflictions in this life they may expect for them, although freed from the curse and unallayed rigour thereof. The promises of it likewise shew them God's approbation of obedience, and what blessings they may expect upon the performance thereof, though not as due to them by the law as a covenant of works; so as man's doing good and refraining from evil, because the law encourageth to the one and deterreth from the other, is no evidence of his being under the law and not under grace.
( Romans 6:14; Galatians 2:16; Romans 8:1; Romans 10:4; Romans 3:20; Romans 7:7, etc; Romans 6:12-14; 1 Peter 3:8-13 )
7._____ Neither are the aforementioned uses of the law contrary to the grace of the Gospel, but do sweetly comply with it, the Spirit of Christ subduing and enabling the will of man to do that freely and cheerfully which the will of God, revealed in the law, requireth to be done.
( Galatians 3:21; Ezekiel 36:27 )