Why? Do you even understand it? In case you don't, that line and the lines before and after it are talking about a potential riot in jail/prison. In those situations, inmates' weapons are whatever they can find, and in some situations they put solid objects (usually not padlocks though since padlocks aren't issued in jails/prisons) in socks so they can hold it by one end and smack people with it. It's a lot more painful then getting hit by a fist.