I know that I have noticed this before today, but the lectionary inserts “Thus says the Lord” in places where it is not really there.  For instance, the Old Testament lectionary reading for yesterday begins:

Thus says the LORD:
Say to those whose hearts are frightened:
Be strong, fear not!
Here is your God,… (Is. 35.4a, emphasis added)

Yet when I went back and looked at the Hebrew text “Thus says the Lord” is not there.  I suppose this is to signal to the hearer that this is prophetic speech.  However, I would think that this would be readily apparent when the lector says “A reading from the Book of the Prophet Isaiah” (or something to that effect).

Oh well.  I do not suppose that this is really that big of a deal.  And, the average lay person probably could go their entire life without ever noticing this.  I just wonder if there is any particular explanation of why this is done.