Yanniru, a good theologeon could probably write a small book on this question. I will do my best.
If I understand you properly, what you are saying is that Christians think they can do away with the Law after recieving salvation. Sometimes I wish that were true.
Now, you must keep in mind that the Torah [containing the Mosaic Law] was given to Moses at Mt. Saini, pertains to the Jews, is ritualistic [having to do with animal sacrifice, cleansing etc] and served both as a symbolic reference to the Messiah [lamb without a blemish slaughtered on the Passover for the remission of sin] and as a means for God to show us, just how far we have fallen and are separate from Him. Maybe I should thank God I don’t have to slaughter animals for the remission of my sin.
As an aside, the Orthodox Jews have a come along way in preparing the Temple in Jerusalem for the coming Messiah---don’t ask me to explain why they don’t simply accept His first coming, except that the Bible said they wouldn’t!
So, the question becomes, what relevence does the Law [Ten Comandments] have for the believer. You can’t know the answer to this without first understanding why Jesus came, died on the Cross and was resurrected. Jesus came to ransom—free us—from the law. NOT from obedience to the Law. There is an old saying that goes—"there is no one more miserable than a disobediant Christian". I can personally testify to the veracity of this statement. I am obediant to the Law out of love and respect for the One who shed His Blood for me and died for my sins—not as a means to get to Heaven. Besides that He won’t use me if I’m disobediant.
If I might wonder off-topic a little, it has occurred to me recently that there are some parallels in nature, for my Redeemer. Though this no longer suprises me—I can’t help but marvel at it!
Photons are theoretical constructs that have a dual-nature. Yet, if they didn’t exist, the electrostatic-force that gives matter the illusion of reality, would dissapate. Jesus was God in the flesh, had a dual nature and was the Creator of the uni-verse. Also, the spiritual realm is the highest reality, the [not really real] reality owes its existence to, and is subserviant to, the higher reality—the third heaven.
Uni [one] verse [words]---"In the Beginning God Created the Heavens and the earth.." All of the wisdom in nature reduced to the spoken Word of God.
And finally, before life can arise from inert matter, it must first be Ransomed from the laws of nature, specifically the laws of chemical equilibrium, entropy laws etc.
I hope I was some help to you. At least maybe I will stimulate some conversation around here.
"Let the Heavens Declare the Glory of His Name"