No Christian in the world follows all the laws given in the Old Testament. No Christian even attempts to follow all the Old Testament commands. Regardless of how a person views his obligation towards the Old Testament, the keeping of the laws regarding temple worship and sacrifice is impossible in this present day. Very few Christians are concerned about their inability to offer a burnt offering in the temple. Very few Christians attempt to keep other commands. Most Christians are not concerned if their garments contain fibers from different kinds of materials or if the meat they are eating falls into the category of “clean”.
Why Christians do not keep all the Mosaic law? The typical answer given to this question breaks into three categories the laws given to Israel at Mt. Sinai. Ceremonial laws were those which governed the worship of the Israelites. Civil laws were those given to govern the operations of Israel as a nation and her people as citizens. Moral laws were those laws which summarize God’s universal standards of right and wrong (the ten commandments are usually cited as an example of the moral law). The common explanation asserts the ceremonial laws are fulfilled in Jesus, and thus are no longer needed. The civil law is no longer needed because God does not at this time have a self-governing nation as His people on earth. The moral law is the only portion of the Mosaic law which is still binding on people today.
This author prefers a simpler view to the classic one given above. The Christian is under no obligation to obey the law of Moses because Jesus has fulfilled the law of Moses and because the church is not Israel. The law given to Israel was intended for that nation from the time of Moses until the time they finally and fully rejected their Messiah. The law given to Israel was always limited in its scope, purpose and duration. Christians today are under obligation to keep the commands given to believers in the New Testament. Christians have no responsibility to observe a Sabbath because that law was in no way repeated to the church. Instead, Christians are under obligation to do something that is not found at all in the Old Testament- gather together every Sunday with other Christians. When the New Testament repeats an Old Testament command Christians are bound to obey it, but asking Christians why they do not follow all the Old Testament laws is a bit like asking an East Berliner why he doesn’t follow all the laws of Communist Germany.
This does not mean the New Testament Christian disregards the Old Testament. Some of the laws given in the New Testament are summations of Old Testament laws. For example, the New Testament forbids immorality but does not describe what that is. To understand what God defines as immoral sexual behavior one has to read the Old Testament. The Old Testament also gives the historic and moral foundation on which New Testament commands are based. When Jesus was asked about divorce, he pointed to the events of creation recorded in Genesis 1-3. The Christian does not scorn the Old Testament but reads and studies it to learn the character of His God and the nature of the requirements God places on His people.
Because God’s character does not change one would expect significant overlap between the commands given to Israel and the commands given to the church. One would expect similarity between the Law and New Testament commands. One would expect the same basic principles to be at the foundation of God’s commands to His people. One would expect certain unalterable, moral laws to be universally applied to all men. This is exactly what we find when comparing the laws of the Old and New Testament. Christians don’t follow the commands of the Old Testament because God has given in the New Testament the commands which He expects believers of this age to obey.