Infertility is one of the most painful trials a couple can face. Thankfully, modern medicine has bestowed the blessing of children upon countless families, and one source of infertility affecting Jewish couples - a woman's conception date preceding her mikveh date - is being dealt with effectively today by Nishmat's yoatzot halachah (women halachic advisers). But Sarai did not have recourse to modern solutions and, like so many women since then, she blamed herself for her childlessness.

A remarkable midrash casts the years of childlessness of the forefathers and foremothers in a different light. Why were the forefathers and foremothers barren, asks the Talmud (Yevamot 64a). Because the Almighty yearns for the prayers of the righteous.

To what prayers are the rabbis referring? The Jew grows through prayer, reaching out to God with his hopes and yearnings. But it seems to me that the rabbis had in mind another facet of Abraham and Sarah's prayers. Abraham's most famous - and lengthy - prayer was for the welfare of the people of Sodom. I believe the Talmud is telling us that while Abraham and Sarah yearned for children, God wished them first to be involved in the world around them. God wished Abraham to pray for the people of Sodom, to bring the message of monotheism and morality to all the families of the earth. Rather than focus on their own family, God wanted all of Abraham and Sarah's energies directed first to the world around them.

In a similar vein, Bereshit Rabbah compares Abraham to a tightly-covered bowl of fragrances, in a forgotten corner. Left to its own, no one would benefit from the perfume. But jarred and jostled, the bowl would share its fragrance with the world around. That is why, says the Midrash, God commanded Abraham, "Lech Lecha", "Arise and go" from your comfortable corner! Jarred and jostled by life's challenges and trials, Abraham and Sarah's fragrance wafted throughout the world.

How often are we distressed by life's challenges, not recognizing a blessing in disguise. Jarring and painful as they may be, it is life's challenges that enable us to follow in the footsteps of Abraham and Sarah and make an impact on the world.