“Shook out the folds of my robe”
I also shook out the folds of my robe and said, 'May God likewise shake out of His house and possession every man who does not keep this promise.' (Nehemiah 5:13 BSB)
What it sounds like today
Nehemiah oddly shaking out his clothes mid-speech.
The cultural key
Shaking out one's robe looks like a random fidget until you know what the garment's fold was. The loose fold at the chest or lap of an outer robe functioned as a pocket, where a person carried coins, grain, or goods. To grip that fold and shake it completely empty in front of an assembly was a sign-act: it made the curse visible. Nehemiah's words spell it out, 'May God likewise shake out of His house and possession every man who does not keep this promise. May such a man be shaken out and have nothing.' The emptied fold is the fate of the oath-breaker, acted out. The people answer 'Amen,' sealing the self-maledictory oath. Paul does something similar when he 'shook out his garments' against those who rejected his message (Acts 18:6), and Jesus tells his messengers to shake the dust from their feet (Matthew 10:14): the body enacts the verdict.
Recovered meaning
Nehemiah shaking out the fold of his robe is an enacted curse, not a nervous gesture. The garment's fold was a pocket for valuables, so emptying it dramatized the oath: may God shake every promise-breaker out of house and possessions until he has nothing.