Hold Forth Meaning

(idiomatic) Talk at great length; expatiate; harangue.

Example: 1913, D.H. Lawrence, Sons and Lovers, chapter 5
  The girls all liked to hear him talk. They often gathered in a little circle while he sat on a bench, and held forth to them, laughing.
1918, W. B. Maxwell, chapter 2, The Mirror and the Lamp[1]:
  That the young Mr. Churchills liked—but they did not like him coming round of an evening and drinking weak whisky-and-water while he held forth on railway debentures and corporation loans. Mr. Barrett, however, by fawning and flattery, seemed to be able to make not only Mrs. Churchill but everyone else do what he desired.