Avraham came to eulogize Sarah and to cry over her. (Genesis 23:2)
Rashi cites the Pirkei D’R’ Eliezer (32) and Yalkut Shemoni (102) that Sarah died as a result of hearing about the Akeidah (Binding of Isaac) and learning that her son had nearly been slaughtered.
The question is: Why did Hashem cause Avraham to lose his beloved wife as a result of the incredible spiritual fortitude he displayed at the Akeidah?
Rav Eliyahu Dessler, ZTL explains that Hashem was testing Avraham to see whether he would question His ways at precisely a moment when Avraham may have justifiably felt he was deserving of blessing.
The lesson here is a powerful one. Oftentimes we perform a very big mitzvah or chesed, and shortly afterwards, we find that we are experiencing great difficulties in an aspect of our lives.
We might be tempted to ask, “Hey! Hashem, why aren’t You looking out for me right now? Am I not being a good Jew? Can’t you see that I’m trying to get close to You and help your children?"
But this type of talk is not the Jewish way nor supported by the Torah.
It is precisely at these moments – when we may feel entitled to blessing and reward – that the true level of our commitment to forge ahead with Torah and mitzvos are revealed.