Just guessing here-- but gird and girdle have the same root- the idea of a belt or sash- and i suspect gird (ing) ones loins- was the equivalent of putting on a jock strap -- protective clothing --before going off to fight (or gallop away on a horse, or march off..)or face what ever adversary was in front of one.

In the past-- civilized people wore loose flowing clothing-- (and barbarians wore trousers!) girdle is still used in the sense of binding-- as in ivy girdling a tree and killing it.--and for us old ladies-- we still remember girdles (even if we don't wear them!)


my other obsession