The Rev. Dr. Martin Luther King, JR addressed the 5th UCC General Synod in 1965. The University of Memphis has the manuscript of the speech, unique in its handwritten edits. You can see a digital copy here.
In their notes on the speech, UM writes:
Dr. King was invited by the predominately-white United Church of Christ to speak on the topic “Man in a Revolutionary World” and in the speech he urged the white churches to join with the black churches in the civil rights
movement. He said it was the church’s role to take the moral lead and condemn racial segregation and discrimination, which many white churches had supported historically. He acknowledged that changes in the law were important but the hardest task was to change people’s thinking and that was a great responsibility of the church.
"It is not enough for the religious insitutions to be active in the
realm of ideas;" Rev. King proclaimed to the synod, "they must move out into the arena of life and do battle for their sanctities."
By the time you read this there will still be some events in Lake Worth to celebrate MLK, including the candlelight March and commemortive dinner.