to shake something so that whatever is clinging to it comes loose and is thrown away
This is the plain motion of shaking out a cloth. You take hold of a blanket, a garment, or the fold of a robe, snap it hard, and whatever was caught in it drops and stays dropped. Every use of this word in the Hebrew Bible keeps that picture in view. Something is clinging, and one sharp shake gets rid of it.
The same gesture turns up in four settings:
- a man shakes out the fold of his robe as a warning of what God will do
- an honest man shakes his hands clean so that a bribe cannot stay in them
- God takes hold of an army and shakes it off into the sea
- a prisoner shakes herself and comes up out of the dust
What holds these together is not the violence but the finality. What is shaken off is not set down carefully to be picked up later. It is treated like grit, chaff, or an insect on a sleeve: worthless, and gone.
That is also why the word can describe rescue. Because a shake removes what clings, the one doing the shaking can be the one getting free. Jerusalem is told to shake herself loose from the dust of exile, and Samson, waking up, expects to shake himself and walk out of the ropes. The action is the same one that discards an enemy. The difference is only who is holding the cloth. Set this beside a word for the ground itself heaving (רָעַשׁ), where the whole thing trembles and nothing is flung loose: here something is always being separated from something else.