Genesis 38 contained a hidden prophecy of the birth of Christ. We might have explained Luke's hidden picture of Christ in Acts 12 by his knowledge of the history of Jesus. There is no explanation for the hidden picture of Christ in Gen 38 except that God subtly directed the actors and the author's view was obscured to see only the parts that painted a picture of Christ. This is why it is called The Director's Bible.
Without assistance, it would be impossible to unpack the whole Old Testament as Genesis 38 was in the previous chapter any time in my lifetime.