From Vanity Fair's fascinating oral history of The Simpsons

Tim Long, co–executive producer, The Simpsons (1999–present): Mr. T [another guest] was telling me the scenes that happened in Rocky III, where he lost. The reason he lost was because his mother needed money for an operation, and so he was paid to take a dive. And I said, "Well, I don't remember that in the movie." And he just looks at me right in the eye and says, "Things you don't see!"

I said to him, "I remember you put out a record called Mr. T's Commandments." And somehow he heard that as "Mr. T, please sing 'Mr. T's Commandments.'" So he sang me the whole song. And I just thought, If I'm killed by a sniper tonight, well, my life would have ended beautifully, because I have been sung to by Mr. T.