What is the role of the Old Testament Law in the lives of Christians?
Well, it’s important to know certain things about the Old Testament laws.
One: They were given specifically to the nation of Israel. Many of the laws were health-oriented (food and clothing), and they were there to make Israel distinct from all other nations. Others were sacrificial, made to represent how bad the crucifixion of Christ was going to be because of the severity required to allow for the remission of sins. Lastly, there were moral laws, made because there is in fact a standard for obeying God. Moral law was given to Israel to show them that they couldn’t possibly fulfill it, because of man’s depravity.
Christ put an end to two of these types of laws: health and sacrificial.
For the health laws, again, Israel had to follow them to distinguish from other nations, and Christians are not all from one nation, so we don’t follow them anymore.
The sacrificial laws are unnecessary because we don’t need animals to be killed for the atonement of our sins, Christ paid that price already.
But moral laws are continuously affirmed in the New Testament. They’re not presented as a duty, but as something Christians do out of a new nature, hence being “born-again” as Jesus describes it in John 3.
Martel explained it excellently, but you might be interested in this other post about Old Testament law as well. God bless. :)