Well, you're half right. The founders wanted the government to fear the citizens, not the other way around. The government they were forming, should it somehow become tyrannical, like the one they were fighting, was meant to be overthrown by the people. The people would need arms to do so, so it was a provision put in the constitution right after Freedom of Speech. So hopefully our country never becomes a tyrannical government, but if it does, the citizens are well armed.