I side with Amos and freedom of expression. I always liked best the verse in the Cherry Tree Carol where Joe says in a huff...Let the father of the baby pick your cherries! It has always "made" the song for me, that human touch.

To address your worry that liner notes might not be read, you might think about recording a very short intro, over soft instrument background, explaining the song's approach, as you might do in a concert setting (haha, esp. if singing in a church). But if your intent in this song is to sympathise with Joseph's plight, I think he could use the press too...go for it w/or w/o intro.