The poppy fields of Afghanistan produce most of the opium, which becomes heroin. These are watched over by the US military, therefore, the flow of horse coming over the border is not going to be impacted. Pharmaceutical companies are the biggest group of dealers anyway. This wall is not going to stop them.
Then, there's the point of the post: people aren't just going to stop doing drugs. They're going to rob more pharmacies, steal from more people who use painkillers, try other, dangerous, chemical compounds; and more Americans will turn into mules.
People aren't doing drugs, because there are drugs. People do drugs, and more get brought in.
Nero blamed Christians for Rome's distruction in 64 AD.
The Essenes of Qumran are thought to be an early Christian group.
The Bible is not Catholic in nature, and it is not Roman in nature either. It is about a single God, not a triune god. Nicea created the doctrine of the trinity, it did not create the Bible. Your theory, or your very own myth, and reality contradict each other.
One can not understand spiritual matters without the Spirit.