What does Martin Luther King mean by justice-equality of rights, equality before the law, equality of opportunity, equality of economic and social condition, or something else?

Based on the article posted on January 14, 2017 by Andrea Estrada on the web page named "The Current" Martin Luther King had a dream and it was the dream of equality and justice for the African-American.

What he means by saying "equality before the law, equality of opportunity, equality of economic and social condition, or something else" That speech, and his exhortation for a society that would judge his children not "by the color of their skin, but by the content of their character," has become the most common representation of King as a symbol of the fight for racial equality.

Equality of rights, I think