Fours are ruled by the Emperor and, like both the Emperor and his throne, they signify stability. The first stage is complete: the invested passion, emotion, brainpower and work gotten past being young and fragile and is now rooted and strong. Established.
This can be positive, a solid foundation on which to build more, or negative, something that has come to a halt and doesn't know how to evolve any further.
Learn the Fours meaning in reversal in our reversed card meanings.