A woman holds a lion's jaws with both hands — not pinning it, handling it, almost stroking. The same infinity sign as the Magician floats overhead. If the Chariot was control, this card is taming.
Strength usually appears where force would ruin it. The other person is defensive, the situation is raw, the kind of thing that hardens the more you press. What that needs is not intensity but time. A lion does not open its mouth because you frightened it.
The same applies inward. This card does not tell you to get rid of the anger or the fear — you cannot, which is rather the point. It says you can carry them along. Doing it while afraid. Being angry and not spending it in the room. The picture is not a lion killed, it is a lion kept close.
Reversed, the reserve has run out. You have been patient right up to the edge of it, or you doubt yourself so thoroughly that nothing moves. This card inverted usually means rest. Patience is not infinite, and mistaking an empty tank for a character flaw only takes more out of you.
Take Strength as an instruction to endure and you will wear out. The strength here is not suppression but handling. The picture is not someone killing the lion; it is someone sitting beside it — that is the whole difference. Enduring and managing are not the same, and pure endurance tips into the exhaustion of the reversal.
With the Devil, the thing to be handled is inside you. With the Sun, it has already been handled. Strength is a card in progress, so whether it is finished or ongoing is read most accurately from its neighbour.