Jamieson, Fausset & Brown, on Esth 7:9

“And Harbona, one of the eunuchs that stood waiting on the king, said: Behold the gibbet which he hath prepared for Mardochai, who spoke for the king, standeth in Aman’s house, being fifty cubits high. And the king said to him: Hang him upon it.”

“Harbonah, one of the chamberlains, said before the king, Behold also, the gallows--This eunuch had probably been the messenger sent with the invitation to Haman, and on that occasion had seen the gallows. The information he now volunteered, as well it may be from abhorrence of Haman's cold-blooded conspiracy as from sympathy with his amiable mistress, involved with her people in imminent peril.”

Imported from an open dataset — not yet checked against the printed edition.