To understand if the OT laws apply to us Christians today, scholars have categorized into the following three categories – Moral law / Ceremonial law / Civil law.

The Book of Leviticus (Old Testament) includes the famous list of laws which will be used as an example to answer this question.

Ceremonial law

Explicitly related to Israel’s worship like the offering animal sacrifices and circumcision.

• Its primary purpose was to point toward Jesus Christ; these laws are no longer necessary after Jesus’ death and resurrection, as we now have direct access to the Father.
• While the ceremonial laws no longer bind us, the principles behind them to worship and love a holy God still apply.
• The Pharisees often accused Jesus of violating the ceremonial law.

Civil law

A guide for daily living in the days of Israel, like the requirement of wearing cross-fiber clothing, and Men commanded not to cut their hair.

• As society and culture in the modern world are so radically different from the days of Israel, these guidelines cannot be explicitly followed.
• However, the principles behind these commands are timeless and should guide our conduct.
• Jesus demonstrated these principles by example by His daily living and conduct while on earth.

Moral law

They are direct commands from God, such as the 10 Commandments.

• These direct commands from God require strict obedience. 
• The moral law reveals the nature and the will of God, and it still applies today.
• Jesus obeyed the moral law completely.

This segregation of the Jewish law into different classes is a man-made concept by scholars intended to understand better God’s reason / motive behind these laws and His nature.

Another approach used by scholars is to look at the Old Testament laws through the eyes of the New Testament. If it is repeated, then it something that Jesus has commanded and established through His teachings.

Most importantly, the law was given for three main purposes; 

• as a reflection of who God is 
• as a guide to what God expects and for us 
• as a mirror to see how well we stand up to God’s standards. 

The law reveals our shortcomings, and since we are unable to achieve its standards, it enables us to focus on looking onto Christ, who became the fulfillment of the law. 

Jesus Christ not only raised the standards of the law to a higher level, but He also showed us that only He could fulfill them. 

Matthew 5:17 (ESV)

“Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.