(This was written a while ago in response to a friend who asked about Saturday vs. Sunday worship and what the Sabbath meant.)
"Jesus liberated His disciples from the tyranny of law. He did this not by abolishing or changing the law but by dethroning it from its place of primacy, revitalizing it, making it subordinate to love and compassion-- to the law the Spirit." (Brennan Manning, Lion and Lamb--The Relentless Tenderness of Jesus)
The Ten Commandments were Plan B. God wanted to lead His people with His eyes. (Psalm 32:8) Plan A was to live in constant fellowship with God--as Adam and Eve did--so that laws were not necessary. But, because the people had "hard hearts" (Matthew 19:8) laws were necessary. They (we!) were so fickle that even while Moses was on the mountain seeing the glory of God, they were building an idol of gold to worship.
When Jesus came, died, and rose again, He reversed the curse of the law. We no longer are bound to the letter of the law, but rather the spirit of the law. We can have PLAN A! We can have fellowship with God and be led by His eyes.
So, what about Plan B? If you look, Jesus exalted each commandment to a higher place. For example one of the commandments (number 6) is, "Do not murder." To keep the letter of that law would mean anything up to killing someone is OK. But, Jesus said, "You have heard that it was said to those of old, 'You shall not murder, and whoever murders will be in danger of the judgment.' But I say to you whoever is angry with his brother without cause shall be in danger of the judgment. And whoever says to his brother 'Raca!' shall be in danger of the council. But whoever says 'You fool!' shall be in danger of hell fire." (Matthew 5:21-22) Set free by the exalted commandment, now you don't just refrain from murdering, you must be kind!
You'll find the same principle in place with the other commandments. "Do not commit adultery" is now "Don't even look with lust or you've already committed adultery." Set free by the exalted commandment, you must not only be physically faithful, you must be emotionally and spiritually faithful--ALL THE TIME.
"Do not bear false witness" is now don't swear at all. No swearing allowed by heaven, earth, or even your own head. Your "yes" has to be "yes" and your "no", "no". Set free by the exalted commandment we must now give account for EVERY WORD, not just the ones we "really mean."
Likewise with the Sabbath, Jesus, in His completing work, has made EVERY DAY HOLY. He has erased distinction between what is holy and what is common.
The Old Law was necessary so that the unclean didn't defile the clean. If someone who was unclean touched a clean person that person became unclean. BUT, now under the New Covenant, if a clean person touches someone unclean the unclean becomes clean! Jesus was free to touch the lepers, to touch the woman caught in fornication, to pick grains on the Sabbath, to heal on the Sabbath. He did not become unclean by doing so. Why? Because He sanctified all things! He makes all things new! (Revelation 21:5)
Jesus established the principle--which has always been the heart of the commandments, but was hidden by the law--that the Sabbath was made for man and not man for the Sabbath. (Mark 2:28)
Further, the Apostle Paul wrote extensively on Christin Liberty. In Romans 14 he wrote, "For one believes he may eat all things, but he who is weak eats only vegetables. Let not him who eats despise him who does not eat, and let not him who does not eat judge him who eats; for God has received him.....One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind. He who observes the day, observes it to the Lord; and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks; and he who does not eat, to the Lord he does not eat, and gives God thanks....I know and am convinced by the Lord Jesus that there is nothing unclean by itself; but to him who considers anything to be unclean, to him it is unclean...."
Do not lose your firm grasp on your liberty in Christ. It was for FREEDOM that Christ has made us FREE!
For our family, we choose to take Sundays as a day of rest and worship. However, if one has to work on Sundays (and sometimes this is inevitable. Aren't you glad that doctors, ambulance drivers, firefighters or even the waitress at the restaurant where you eat after church are working on the "Sabbath"?) they can choose to observe Saturday or Monday as their Sabbath. They must just take time to rest and to acknowledge the Lord. Jesus has fulfilled the Sabbath (becoming our Sabbath rest, it says in Hebrews), making every day holy to Himself--if you walk with God!