I recently posted a comment on the The Bible In Depth blog about the Sabbath and animal sacrifices, and the writer of the original post (But I Don't Want To Go!!!!) raised a number of questions. Since the answers will be somewhat off-topic to his original post, I will answer them here.
"What is the purpose of animal sacrifices?"
The purpose of animal sacrifices is educational. God uses them to teach us about the sacrifice of Christ. They are symbolic. They are a copy and shadow of the real sacrifice of Christ (Hebrews 8:3-6, Hebrews 9:23-28, Hebrews 10:1-10, Galatians 3:23-25). In these verses in Hebrews and Galatians, the term "law" in this context is referring to the law of Old Covenant animal sacrifices and rituals. It does not refer to God's spiritual law (Romans 7:13-25) or to the ten commandments (James 2:8-13). Just as today, a word can mean different things, depending on the context. The word "law" can refer to the spiritual law of God, or to the books of Moses, or in this case to the laws of the Levitical priesthood, that is, animal sacrifices.
Although animal sacrifices are not being used now in this church age, the prophecy in the book of Ezekiel from chapter 40 to the end of the book seems to show that there will be a system of animal sacrifices in the future, no doubt in the millenium. To the best of my knowledge, the conditions described in Ezekiel 47:7-12 (healing waters) have never been fulfilled in history, which is why I say this appears to be a prophecy concerning the temple in the millenium. If I am correct and if animal sacrifices are restored in the millenium, then those sacrifices can be a valuable teaching tool for teaching the people about the sacrifice of Christ.
Another indication that this prophecy has never been fulfilled in the past is the division of the land among all the tribes of Israel as described in Ezekiel 47:13-23 and Ezekiel 48:1-35. That has not occurred since the captivity of Israel by Assyria about 700 years before Christ. So this must be in the future.
"Were the 10 commandments a part of the Mosaical Law?"
Yes. The ten commandments are a summary of God's spiritual law (Romans 7:14). God's spiritual law is love (1 John 5:3). It is summarized as love towards God and love towards neighbor (Matthew 22:35-40). The ten commandments further summarize God's law of love and breaks it down in more detail, with the first four commandments teaching us how to love God and the last six how to love our neighbor, and the ten commandments are still in effect (James 2:10-11). Sin is defined in the Bible as the transgression of the law (King James Version) or "lawlessness" as translated in the New King James Version (1 John 3:4).
As a summary of God's spiritual law, the ten commandments are foundational to both the old and new covenants, and it is part of the Mosaical Law as well as part of the New Covenant. The New Covenant does not replace or do away with God's spiritual law, but rather the New Covenant promises that God will write His law in our hearts (Jeremiah 31:33, Hebrews 8:10, Hebrews 10:16). Jesus in the sermon on the mount taught that we must obey the commandments in their fullest spiritual application, not just the letter (Matthew 5:21-30).
"What was the purpose of the Sabbath?"
There can be many purposes of the Sabbath, and not all are stated because God does not explain every reason for every command, but I think we can discern some of them. The Sabbath gives man much needed rest from the burdens of working six days. The Sabbath provides time for us to draw close to God in prayer and Bible study, to receive instructions from God's ministry, and to draw closer to our brethren in Christian fellowship. I think it is evident that the weekly Sabbath pictures the 1000 year reign of Christ after 6,000 years of man's rule on this earth under the influence of Satan. It can picture the spiritual rest we have in Christ (Matthew 11:28-30).
In addition to the weekly Sabbath, there are annual Sabbaths that help to illustrate God's plan of salvation for mankind.
But there are two purposes of the Sabbath that are stated in the Bible. One, God has used, and I have no doubt He continues to use, the Sabbath as a test command to test the obedience of His people. He used it to test ancient Israel and He specifically calls it a test (Exodus 16:4-5, 25-30). Note from these verses that the Sabbath was part of God's law BEFORE the ten commandments were given and the Old Covenant made with Israel. Also, Christ indicated that the Sabbath was made for mankind (Mark 2:27). The Old Covenant was never made with mankind as a whole but only with Israel. This shows that the Sabbath is not just a ritual limited to the Old Covenant, for then it would not have been made for all mankind, only Israel. So a purpose of the Sabbath can be a test of our obedience.
Secondly, the Sabbath is a sign. It identifies to us who the true God is, that is, the creator. It also identifies who God's people are to God, that is, those who obey Him. There is a scripture that seems to indicate that the Sabbath was made a separate covenent, not part of the Old Covenant, but a different covenant, for the very purpose of serving as a sign between God and His people, in Exodus 31:12-17, especially verse 16.
"Did Jesus fulfill the law?"
Yes. Jesus obeyed the law perfectly, setting us an example. He stated that He obeyed His Father's commandments (John 15:10). Sin is the transgression of the law (1 John 3:4). Since Jesus never sinned (Hebrews 4:14-15), He must have perfectly kept God's law. He also fulfilled prophecy concerning His first coming.
"Does or can the Bible contradict itself?"
All scripture is inspired by God (2 Timothy 3:16-17). God cannot lie (Titus 1:1-3, Hebrews 6:17-18). Therefore, God cannot contradict Himself. Scripture cannot be broken (John 10:34-36).
If there appears to be a contradiction, it is because there is a mistranslation or because there is something about the scripture we do not understand.
I have proved that the Bible is inspired by God by prophecies that have been fulfilled, but I choose to believe that God cannot lie, and that is a part of my faith. So by faith I know that the Bible cannot contradict itself.