We often describe our moods as swinging from good to bad, happy to sad. This mood swinging makes me think of a pendulum and the fundamental difference between static and dynamic. In engineering mechanics, statics is the study of loads acting on bodies that do not move. Dynamics, on the other hand, is the study of loads acting on bodies that are in motion.
A pendulum can either be in static equilibrium (hanging straight down without motion as shown in the picture) or in dynamic motion (swinging from side to side). The difference between statics and dynamics is time. Because there is no motion in statics, time is not a factor. The system is unchanging. Time is required to describe dynamic systems, however. It takes time for the pendulum to swing from the bottom to its highest point (and back) and it therefore requires time to describe that motion.
Think about this: God created time. Time exists because God set creation in motion as He spoke, “Let there be…”. Do you know what this means? God expects dynamic. He is not surprised by your ups and downs. He did not create a world for us that is static, or unchanging. It is dynamic. We live in the linear dimension of time. It keeps going, moving forward, changing.
If you sometimes feel overwhelmed by your changing moods, remember the pendulum. It only stays at the bottom when it stops moving, when it is static. As long as it keeps swinging, it is certain to reach its high points with regularity. Not only that, but its speed is greatest as it passes through its lowest point.
Be encouraged! You have a God who created a dynamic world for you, but who is also faithful and unchanging (or static). Your mighty God is the only example in all the universe that is both static and dynamic simultaneously!