Why people fight for the commandments is because in Galatians it talks about the laws and that they were put here as a tutor, but now with Jesus we no longer need that tutor. The reasoning is that our Lord Jesus has taught us to live in love and through love all things are fulfilled including the commandments. As for defiling the commandments in our hearts and action, the false since that is taught today is Christians no longer sin after they have accepted Jesus as Lord and Savior, and received the Holy Spirit. That is false teaching, no man or woman is perfect. Doubt, worry, and anger will always be there even in the best of us.
James 2
8 If ye fulfil the royal law according to the
scripture, Thou shalt love thy neighbour as thyself, ye do well:
9 But if ye have respect to persons, ye commit
sin, and are convinced of the law as transgressors.
10 For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.
11 For he that said, Do not commit
adultery, said also, Do not kill. Now if thou commit no
adultery, yet if thou kill, thou art become a transgressor of the law.
12 So speak ye, and so do, as they that shall be judged by the law of liberty.
Romans 13:
8 Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law.
9 For this, Thou shalt not commit
adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false
witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.
10 Love worketh no ill to his neighbour: therefore love is the fulfilling of the law.
SO, which of the 10 Commandments can we break now?
Can we now bow to graven images? Take the Lord's name in vain? Worship other gods? Steal from our neighbour? Kill our neighbour? Bear false witness against our neighbour?
Usually its just the 7th day Sabbath that Christians want to get rid of. They well know it sounds too ridiculous to claim that they can break all the other 9 of them.
If you love your neighbour will you kill them or steal from them? OF COURSE NOT!
When Jesus said the two greatest commandments are love God and love your neighbour, he was quoting the Old Testament in Deuteronomy and Leviticus. Loving your neighbour isn't some new thing that Jesus came up with, the people had lost sight of that and were merely keeping the Law outwardly. That's why He said the Religious Leaders tithed mint and rue but neglected the weightier matters of the law like kindness and mercy etc. He said on these two laws, love God and love thy neighbour hang the whole law and the prophets. Love God encompasses the first 4 commandments and love thy neighbour encompasses the last 6 commandments. It isn't as if it is OKAY now to violate any of them now "because Jesus died on the Cross".
WHY did Jesus die on the Cross? is it so we can go break the 10 Commandments?
Titus 2:14
Who gave himself for us, that he might redeem us from
all iniquity, and purify unto himself a peculiar people, zealous of good works.
He died so that you would start KEEPING the Law, not so that you have a free pass to go out and violate it.