What message does the speaker of “Song of the Son" suggest with
the ending "What they were, and what they are to me, / Caroling
softly souls of slavery" (lines 22-23)?

The speaker tells in these lines about the importance of his father in his life.

Explanation:

The message which the speaker of “Song of the Son" suggested was that we the black African Americans have a very painful past. Our ancestors tolerate pain and hardships in their life. We have to remember all their hardships and pain and make this society a better place for us and for our coming generations. He also mentions in this poem that his father was a slave who bears a lot of pain due to white supremacy.

answer; /// the above statement is (true);