Why don’t we obey all the rules of the Old Testament?

You can see that some rules remain the same, some new ones are added, and others change or go away as the child develops into adulthood.  Paul tells us that the Law served as “our guardian until Christ came, in order that we might be justified by faith. But now that faith has come, we are no longer under a guardian, for in Christ Jesus you are all sons of God, through faith” (Galatians 3:24-26).  The Law of Moses was there only for the time of the world’s development up until Christ’s coming.

And remember, the Law was for a particular nation, Israel, and the people of God now includes Jews and Gentiles, not one nation but many nations.  Many of the laws for Israel were nationally oriented (laws of punishment for certain crimes, national observances of religious festivals, treatment of slaves, etc.).  But believers live under the laws of many different nations around the world.  God was also using Israel as a witness to the world of their unique relationship to God, and so some of the laws were designed to set Israel apart from other nations (circumcision required for all males, clean and unclean foods designated, forms of dress, etc.).  Believers today cannot be set aside in the same way.  We give witness to our relationship to God through our moral character, and especially our love.

So, at this time in our “development” as a race we are under a new law, the law of Christ (1 Corinthians 9:21).  It contains many of the same moral requirements as the Law of Moses (at least nine of the ten commandments, the Sabbath law being altered some), but because of what Christ has accomplished by his sacrifice, all of the sacrificial system of the Law of Moses is no longer pertinent.  Christ’s sacrifice has made all the previous sacrificing obsolete.  He is the fulfillment of all those sacrifices.  And the laws about diet and slavery and so on are also obsolete.

So now we might diagram things this way:

There will yet be another development in the way we are governed in the kingdom, when Jesus returns.

See what your co-worker thinks of this.  Ask him if he has been a fallible parent if he has changed any of his rules for his kids.