Abinadi declares that the priests of Noah are not correctly intepreting the law of Moses. Rather than be seen as denying the law (as the priests undoubtedly hoped) Abinadi stands as a champion of the law. He has placed the priests in precisely the position they had attempted against Abinadi.
Abinadi gives a list of ways in which they priests are in violation of the law of Moses:
Abinadi's first accusation certainly sounds bad, but how is it a violation of the law of Moses? There is nothing in the law of Moses that prevents people from being well-to-do. There is nothing that suggests that poverty is preferable. To get a better idea of what Abinadi is suggesting, we need only look at the other two examples we have to this point in the Book of Mormon where men of God have railed against riches. Jacob clearly objects not to riches, but to the unequal distribution of riches (see Jacob 2:17-19). Benjamin has the same concern, and specifically discusses the responsibility of those who have toward those who do not (see Mosiah 4:16-25).
Abinadi is following what appears to be a consistent Nephite reading of the law of Moses, that it desires the common good of the people, and counsels against the social and economic separation that riches can bring. It is this principle that the priests are violating. That they might have riches is not the issue, but that their hearts are upon them. They desire the riches, power, and position. They desire to be placed above the populace (remember that they are even seated above those who come before them - Mosiah 11:11). It is this inequality that is the violation of the law as the Nephite prophets interpret it.
The second accusation concerns whoredoms and harlots. As has been discussed previously, this presumes social definitions. It is virtually certain (though unstated) that the priests of Noah justified their multiple wives on the basis of Solomon and David, as did the Nephites who first lived in Nephi during Jacob's times. Once again, Abinadi is preaching against the specifics, and in this case most likely the marriage to outside women and the adoption of foreign religious practices that may have included ritual sex acts. These are not simply moral sins, but open acts of rebellion against God.
The last accusation is that the priests are teaching these things to the people. Clearly the priests have been the means of integrating the new practices into the inherited religion of the people. Their task has been to find ways, such as an appear to David and Solomon, to ease the entrance of these new ideas. In this role, the priests are directly at fault for the beliefs of the people, who have been swayed by them, and now believe enough that they would not only not recognize a prophet of God, but would willingly turn him over to his inevitable death. In this accusation, Abinadi foreshadows Christ's teaching on the Sermon on the Mount: "Matt. 5:19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven…"