People might not get all they work for in this world, but they must certainly work for all they get.

Two claims sit together here, and the order matters. Effort does not guarantee a return, since plenty of people work hard and are denied, and that unfairness is real rather than a failure of attitude. What follows is not that effort is pointless, only that nothing arrives without it, so the work stays necessary even when it is not sufficient.

Hold both of those when you are tired. Keep doing the part that is genuinely yours, and stop reading a poor outcome as proof that you did it wrong. Where the obstacle is structural rather than personal, name it plainly instead of turning it inward.