the.com/ebb and flow

means The natural pattern of decreasing and then increasing again, used for anything in life that cycles between low and high points.

from Straight from the tides. 'Ebb' traces back to Old English 'ebba,' describing the sea's retreat from shore, while 'flow' comes from Old English 'flowan,' meaning to stream or rise — both are old Germanic words sailors and coastal folk lived by, since knowing the tide's rhythm was survival, not poetry. The pairing became a fixed phrase for any rise-and-fall pattern, with the sea's literal push and pull turning into a metaphor for fortune, emotion, and everything else that refuses to hold still.