We are taught about Sarah that her entire life was good. She was happy in the service of G-d in all circumstances. Life events and divine trials did not harm her joy in the service of G-d, which was the center of her life.
This gives us an opportunity to discuss the verse which tells us to maintain our joy. It appears in the passage of rebuke in the Torah, "Because you did not serve your G-d in joy and with a good heart, due to the great abundance, you will serve your enemies..." [Devarim 28:47-48].
We might have interpreted this verse as discussing somebody who did not serve G-d at all, even though he could have served G-d with joy. This would imply that the verse does not demand serving G-d in general with happiness but refers to serving G-d in general. But the Rambam makes it clear that the verse specifically mentions joy, and that the punishment mentioned is also relevant for one who served G-d but not in a joyful way! "Joy refers to the fact that a person should be happy when performing the mitzvot and in the love of G-d, which G-d commanded as an important way of service. And anybody who refrains from being happy deserves to be punished, as is written, 'because you did not serve your G-d in joy...'" [Hilchot Lulav].
Due to the Great Abundance
However, even based on the commentary by the Rambam, we might say that there is no obligation to be happy under all circumstances but only as is written in the verse, "in joy and with a good heart, due to the great abundance" – that is, "as long as you had everything good" [Rashi].
To counter this, the ARI explains in a novel commentary that the "abundance" in the verse does not mean "due to" the abundance but rather "more than" the abundance (Introduction to the Chapter on Mitzvot). The joy that one must feel on performing the mitzvot is infinitely greater than the joy of worldly matters, and even greater than being close to G-d in the world to come! According to this interpretation of the ARI, the verse obligates us to be happy in our service of G-d under all circumstances and without any conditions, even if the person does not feel that things are good. Joy is critical, as can be seen from the harsh punishment for a lack of joy.
This is very hard to understand. Is it reasonable that a Jew who overcomes his evil inclination and serves G-d in thought, speech, and actions, will be punished severely only because he lacked the proper level of happiness? The answer is that joy is not a good addition to the service of G-d, rather it is something that lies at the very basis of the way we view the world.
When a Jew is happy in his service of G-d it shows that he understands the concept of Divine service. If one treats the labors of G-d as a relationship between a worker and an employer, he will have no patience for the fact that the "employer" does not accept full obedience and loyalty but also demands happiness! Doesn't He at least leave me to take charge of my own mood?
However, a person who sees himself as the son of the Holy One, Blessed be He, sent here to fulfill a wonderful and exalted mission by serving G-d in this world – "to provide a dwelling place for Him down below" – has a heart filled with joy because of his vital goal. He understands that he must overcome any difficulties. Our Matriarch Sarah set an example of just this phenomenon – a "sign for her offspring." She lived through many difficulties that were all based on her Divine mission, with a desire to fulfill His will, and it was therefore unthinkable that she would do anything without being happy.
Happiness brings Greater Happiness
The Tanya has a remarkable insight based on this concept in his book Likutai Torah. The punishment that is due to everybody for a lack of joy results from various acts of sin by way of a lack in his holy service. One is not punished for a lack of joy but rather for the fact that if he had shown real joy he would have been able to block the punishment and cancel it! A person who is sad is punished for his sins and his lack, without any leniency, as would have happened if the person had acted out of joy.
The Baal Shem Tov used to interpret the words of Tehillim, "G-d is your shadow" [121:6], that just as a shadow takes on the form of a human being, so – as it were – the Holy One, Blessed be He, copies what mankind does. When a man is happy, the Holy One, Blessed be He, is correspondingly happy, and "views him with a pleasant face," such that there are no thoughts of punishment and suffering. And then the Holy One, Blessed be He, finds other ways to solve the problem of human sin.
