Why did martin luther king used work, speeches, songs and the bible in his speech

Because he was very godly and please answer my question

The native americans, spanish, french and americans all name places in our state. the word “arkansas” came from the quapaw indians, by way of early french explorers. at the time of the early french exploration, a tribe of indians, the quapaws, lived west of the mississippi and north of the arkansas river.