My heart is inditing a good matter; literally, bubbleth with a good matter—is so full of it that the matter will burst forth. I speak of the things which I have made touching the king; or, I utter that which I have composed concerning the king.
My tongue is the pen of a ready writer. It is noted that only "psalms of high and solemn import" have formal exordia of this kind, announcing the intention of the writer.