According to Martin Luther King Jr., the difference between just and unjust laws is that an unjust law is when the majority inflicts on a minority that is not binding on itself. a just law is when the majority makes the minority follow its lead.
From my point of view this is an important distinction due to the fact that people are usually influenced by something that the majority is supporting, which means give importance to “just laws”. It makes a difference in the way people live their lives due to the environment that they may be in. For example, New York City is a liberal dominated city meaning that a lot of decisions will be based upon liberal acts and beliefs.
An example of an unjust law were the Jim Crow laws. It promoted segregation and was not beneficial to humanity but rather detrimental as it caused a lot of hostility. On the other hand, an example of a just law is the “Title VII of the Civil Rights Act of 1964” that prevents discrimination.