I keep the staff in my own hand. I keep possession; I retain the right. The staff was the ancient sceptre, and therefore, figuratively, it means, power, authority, dignity, etc.
“Give up your staff, sir, and the king his realm.”
“Thou mayst see me at thy pleasure, for I intend to strike my staff at yonder hostelry.” —Cæsur Borgia, x v.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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