In his "I Have a Dream" speech, he dwells upon the idea of the principles and promises stated in the Declaration of Independence. Martin Luther King jr says that the architechts of the nation, those who signed the Constitution and the Declaration of Independence were signing a promise to which every American was to fall heir. This would include African Americans, who must be guaranteed the same unalienable rights of life, liberty and the pursuit of happiness.
The importance of spreading the faith was to save Indians from heathenism and prevent them from falling under the sway of Protestantism. Enslaving the Indians was justified as a means of liberating them from their own backwardness and savagery and enabling them to become part of christian civilization.
