One of my favorite messages about grace by Derek Prince, Derek talks about how many churches incorporate the law into their church requirements. Whether it is by what you must wear or not not wear, what day you fellowship on, not using musical instruments, not eating meat, etc.
He goes on to point out that if you drove your car to church, according to the requirements of the law concerning the sabbath, you should be stoned. Not only that if someone saw your do it and they don't stone you, that person should be stoned. There's no mercy involved for breaking the sabbath.
As believers we enter into the rest of God, completing all of the requirements of the law by walking in the Spirit. We fulfill the spirit of that law. If you do a study in the Word on the word "sabbath", looking at the law from a New Covenant perspective, it will become more obvious to you that the sabbath requirements are fulfilled in Him.
Moses told the Israelites not to add or take away from the law. The Law is one single and complete system. "It came through Moses and terminated through Jesus Christ."
He says that "most Christians want to play around with the law, and they want to keep those parts which suit them, and fit into their particular religious views and culture, and ignore the rest, and that is not permitted."
"If you're going to keep the law, you're a debtor to keep the whole law."
There is also curse on those who start and do not continue in the law.
Scriptures like Isaiah 58 shine more light into our walks. We're not supposed to say our own words (of the flesh), doing our own pleasure (outside what is given to us by the Spirit of God). We could judge ourselves more strictly on that and receive a greater blessing from God. It also points to good works (now done in the Spirit) where we're busy doing the things that please God.
There is a part two, and both of these are VERY good. There is nothing like a fresh revelation of grace in our lives to show us what God wrought for us in Christ, and to reveal what burden He set us free from.
Enjoying Gods Grace 1 - Derek Prince (audio only) - YouTube