Most parents don’t need to be told that you treat children differently at different stages in their lives. Adult freedoms and privileges are denied to give children a chance to mature. Parents control their children’s diets, bedtimes, and their access to cars and alcohol. These denials aren’t from a lack of love, but precisely because parents love them so much. Minor children learn respect, patience, wisdom, self-control, and consideration for others when they are compelled to live under their parents’ rules.
The key to understanding the differences between the Old and New Covenants is to realize that God chose to treat people before the time of Christ as though they were minor children. It’s not that people today have evolved to be smarter and more responsible. It’s people’s sinful rebellion against God that caused them to lose their understanding of God and his ways. God decided to rebuild that understanding slowly, wrapping his gospel mercy in a context of laws and rules. St. Paul wrote to people who were used to this law experience: “Before this faith came, we were held prisoners by the law, locked up until faith should be revealed. So the law was put in charge to lead us to Christ that we might be justified by faith” (Galatians 3:23,24).
What this means for today is that we need to pick our way carefully through God’s words in the Old Testament. Some of what is written there was for believers when they were considered minors. You’re big now.