Deuteronomy 17:14–20 is known as the paragraph of the king. It is a provision in the Law of Moses that says what the king can and cannot do. For example, in verse 16 it says, "He shall not multiply horses to himself." That does not mean he cannot have any horses, but rather that he cannot have an excessive amount, such as Solomon’s thousands of horses. It also says, "Neither shall he multiply wives to himself, that his heart turn not away: neither shall he greatly multiply to himself silver and gold" (Deuteronomy 17:17). How might a king like Noah have interpreted this? The law prohibits him from amassing too much gold and silver, but who decides what is too much? Noah imposed a twenty percent flat tax. While twenty percent may not seem excessive to us today, to people in the ancient world it was quite a lot. And, might the general population have considered twenty percent to be a prohibited "multiplying"? Twenty percent is, after all, twice a tithe. But, perhaps it is possible Noah saw this as providing ten percent for the Lord—for the priests to run the temple and religious practices—and then he allocated the other ten percent for himself, the king, for public needs. There is actually some precedent in ancient Israel for each—the king and the temple—to receive ten percent on some occasions. Similarly, Noah may have rationalized that his right to collect and receive these funds was as great as the right of the priests.
As far as wives are concerned, we have clear indication in Mosiah 11:2 that Noah "had many wives and concubines." Whatever additional regulations or commandments Lehi may have given concerning marriage, Noah’s problem, at least under the prohibition in Deuteronomy 17:16, was that he had too many wives. His excess in this regard was clearly not acceptable in the eyes of Abinadi, who was commissioned by the Lord to preach repentance to Noah and his people. It appears that Noah also rationalized his lavish building program (Mosiah 11:8, 13). We do not have the details on all the other ways he and his priests apparently had interpreted the law that had allowed or caused himself and his people to commit sins.