When a person experiences difficult times, he should realize that even if the suffering is not because of a sin he did, it is often to test whether he will accept Hashem’s decree wholeheartedly. He should not let up on his service to Hashem, because the tribulations were sent to display our love for Him and increase our reward. This is how Hashem behaved with Avraham Avinu and with David Hamelech, and He does so with the tzaddikim of every generation according to their level. If a person succeeds in withstanding the pressure and holding strong, putting Hashem’s service above his personal convenience, he will receive inconceivable reward.