TL;DR:
a: a force that brings good fortune or adversityb: the events or circumstances that operate for or against an individual
People think hard, they work hard, they know how to create opportunities. The result is the fruit of hard work.
Hard, but kind of predictable.
Other set of people think hard, may work as hard, but can’t create opportunity. One day someone/something (the force) provides them with the opportunity and they seize it.
Luck. Different skill sets. Not as predictable.