"A Song for You" is an apology that arrives after the statute of limitations has expired. Donny Hathaway recorded it in 1971 as a confession from a man who has done wrong, knows it, and has no way to make it right except to sing the truth. He has hurt someone he loved and is now performing his regret in public, hoping the person he wronged is somewhere in the audience. An apology delivered too late for a private conversation.