You may have heard the old parable:
Good luck and bad luck create each other and it is difficult to foresee their change.
A righteous man lived near the border.
For no reason, his horse ran off into barbarian territory.
Everyone [people] felt sorry for him.
[But] His father spoke [to him]:
“Who knows if that won’t bring you good luck?”
Several months later his horse came back with a group of [good, noble] barbarian horses.
Everyone [people] congratulated him.
[But] His father spoke [to him]:
“Who knows if that won’t bring you bad luck?”
A rich house has good horses and the son mounted with joy/loved riding.
He fell and broke his leg.
Everyone [people] felt sorry for him.
[But] His father spoke [to him]:
“Who knows if that won’t bring you good luck?”
One year later the barbarians invaded across the border.
Adult men strung up their bows and went into battle.
Nine out of ten border residents were killed, except for the son because of his broken leg.
Father and son were protected/both survived.
Hence: Bad luck brings good luck and good luck brings bad luck.
This happens without end and nobody can estimate it.
Note: The “luck” part is nonsense, of course.