strong: possessing force that does not give way, whether power that overwhelms or hardness that will not bend
This is the everyday adjective for whatever has force and keeps it. Its picture is a thing that cannot be pushed aside: a powerful arm, a fierce wind, an enemy you cannot beat, a famine that will not lift, a forehead that will not bend. One word covers all of these because they share a single idea, the refusal to yield under pressure.
The uses fan out along two lines from that center. One line is sheer power, whether of a nation, a storm, or God himself. The other is hardness or severity, the grip of a sickness or the stubbornness of a person who will not be moved. Sitting between them is the comparative use, which simply marks one side as the stronger, the one you cannot overpower. None of these is a separate word; they are the same plain adjective taking its color from what it describes.
The most weighty use is a fixed phrase. Over and over the rescue from Egypt is said to have been done with a strong hand, and later prayers and prophets reach back to those words as the standing proof of what God can do. The word for a strong man is lifted here to name a power that nothing in the world can resist.