Emerson gave Thoreau the property on Walden Pond in Concord, Massachusetts; where Thoreau spent about two years living away from the society.
After Rosa Parks refused to give up her seat through an act of disobedience, Martin Luther King Jr assisted with the boycotting of Alabama public transportation. A few decades after he was born at age 32, he wrote an essay.
Thoreau thinks of injustice as friction or tension that can wear the machine down. He wrote for the magazine of the Organization of American Historians.
The chief difference between Thoreau and King is the context in which each one of them operated. But they both want to get the point across that you must do something to change unjust laws because they are wrong and can take your God given freedom away.
King is saying that just laws should be obeyed because they are the law and they are morally right. You can't say that what ever happens in Atlanta does not affect you in Birmingham. King stated that while in college.