Stability, Physical, Labour, Earthly things, Four corners of the earth, Four directions elements.
You get things done, the world, material things, instincts, order and the stable square.
Four deals with the grounded nature of all things, solidity, calmness and home.
A recurrence of Four in your life signifies the need to get back to your roots, center yourself or even "plant" yourself.
Fours also indicate a need for persistence and endurance.
Planet - Mercury