God's law always accuses us. Even when we are trying to obey God's commandments and keep His word, the law is always there reminding us that we are obeying imperfectly, that our motives are not pure, our desires not clean.
Numbers 32 is an example of when the law falsely accuses. The Reubenites and the Gaddites, being cattle ranchers, found good grazing land across the river Jordan, and asked that they be allowed to settle in that land.
Moses is the quintessential lawgiver (John 1.17). And Moses here accuses the brethren of being unwilling to go to war against their enemies, of being slackers, and of discouraging the people of Israel.
But Moses was wrong. And this is one of the messages of Numbers 32. The law was accusing, but the accusations were false. The Reubenites and Gaddites explain their reasons, and offer to go to war.
When the law is plain, it's not wise to argue. If I hate someone, the law rightly accuses me with "Thou shalt not kill." But if there is no plain commandment, and I'm guilty, I might be dealing with a false accusation.
If I drink a beer, and feel guilty, that's a false accusation. If I think it's wrong to dance, it's a false accusation. There's a multitude of such guilt, and it's not wrong (as we see in Numbers 32) to argue back against the accusation, against the false guilt.