And here are King’s early thoughts on this biblical passage, written in 1953 as a Ph.D. student:God (Amos)5:21:24—This passage might be called the key passage of the entire book. It reveals the deep ethical nature of God. God is a God that demands justice rather than sacrifice; righteousness rather than ritual. The most elaborate worship is but an insult to God when offered by those who have no mind to conform to his ethical demands. Certainly this is one of the most noble idea ever uttered by the human mind.One may raise the question as to whether Amos was against all ritual and sacrifice, i.e. worship. I think not. It seems to me that Amos' concern is the ever-present tendency to make ritual and sacrifice a substitute for ethical living. Unless a man's heart is right, Amos seems to be saying, the external forms of worship mean nothing. God is a God that demands justice and sacrifice fo can never be a substitute for it. Who can disagree with such a notion?3Notice how King wrote the topic (God) and his source (Amos 5:21:24) at the top of the note card for easy reference.

one of King’s note cards on the Old Testament’s Book of Amos which includes the linesBut let judgment run down as waters, and righteousness as a mighty stream. These lines would feature in many of King’s speeches—including his famous “I Have a Dream Speech,” where King said: …we will not be satisfied until justice rolls down like waters, and righteousness like a mighty stream.