Bob Murphy's primary argument was that while trade deficits are often seen negatively, they are actually not that bad and can actually be beneficial. When the gold standard was abandoned by the US the economy saw growth resulting from the new standard of the dollar that was no longer connected to gold. Unlike other countries, the US can run with a trade deficit because the US currency has become the standard currency for other nations as well.
Connecting to the Bible, Murphy talks about Deuteronomy and how God allowed for some nations to have growth over other nations and have power over them. As well as, trade requires both parties to agree, requiring peace and stability between two or more nations. Ultimately, God rules but allows for earthly rule and dominion and allows for some nations to have a setting standard for other nations and set that standard.