I just heard the most interesting thing by Beth Moore -

People normally turn to legalism (the "rules" of Christianity) when they are empty and have not had a fresh Word from God or God is not priority in their lives. When they are not holding onto God fully then they have to have something to hold onto and that usually becomes the "rules of men" because it makes them feel safe.

Finally, all of you be of one mind, having compassion for one another; love as brothers, be tenderhearted, be courteous.

I Peter 3:8