In our class about false teaching, we learned there that there are two main ways the church falls into error today. These are not associated with a particular denomination, but one or the other can be observed in any number of church traditions.
The first is legalism. Some churches may require adherence to laws that are impossible to keep. (This is the same problem that the Jewish people faced.) When this kind of error is present, it often leads to the church either diluting the law, to make it easier, or inventing new rules that are easier to keep, but not biblical.
The second way churches can go astray is by espousing antinominanism. This is a big word which basically means that the law is no longer of use to Christians because it has been superseded by the gospel. In this case our behavior really doesn’t matter.
Lutherans, of course would say we need a balance between law and gospel. Both are necessary, neither should dominate. We must teach the law in order to see that we are sinful people who can’t save ourselves. We must teach the gospel to understand that through the sacrifice (once and for all) of Jesus we are saved saints of God. We will never be able to keep the law perfectly, but good works are our response of gratitude to the One who loved and saved us.