Just because something is legal doesn’t necessarily make it good. This is because for Christians, our ultimate standard of morality does not come from the government, but from God.
It is important for Christians to remember that we are called to obey governing authorities. In the United States the legal age for substance use is 21 and though this may seem arbitrary to some people, it’s actually not. Substances can affect teen’s brains much more easily than adult brains. Though there may seem to be many short term rewards for using drugs, it is important to keep in mind the long term consequences that can come with drug use.