Insights into Sukkot by Rav Re’uven Ungar of Sha’alvim.
The Mishnah in Masechet Sukkah (53a) remarks that during the Simchat Beit HaShoeva celebrations “..some people proclaimed ‘happy is our youth that did not embarrass our mature years’ , while others said ‘happy are our mature years that atoned for our years of youth.’..it was said that the elder Hillel proclaimed – ‘if I am here, everything is here, if I am not here, who is here?’ ”
Why did the songs of the Simchat Beit HaShoeva focus on issues of purifying oneself from sin? What is the meaning of the words of Hillel?
Rav Soloveitchik, of blessed memory, explains as follows (recorded in Reshimot Shiurim, page 282): Chag Sukkot is the festival of purification as it follows the purification of Yom Kippur. Therefore, the motif of the songs and praise focus upon purification and forgiveness from sin.
The words of Hillel also relate to cleansing from sin. Hillel declared in a strident tone that an individual is responsible for his actions. He may not abdicate responsibility and place it upon others.
When others mock him, an observant person must respond “If I am here- by myself- everything is here”. The individual may not claim that others will fulfill the Torah in place of him. “If I am not here, who is here?”. A person is entirely responsible for himself. When a person feels this responsibility- he is likely to repent and to become observant.
The foundation of song in the Simchat Beit HaShoeva is the verse in Tehilim (103:2,3): “My soul blesses Hashem, and may it not forget what He has done, who has forgiven me for my sins who has healed all of my sicknesses”. Similar to those who have been rescued from dangers and are required to thank Hashem, those who receive atonement from their sins are required to thank and to sing to Hashem. This constitutes the foundation of the celebration of the Simchat Beit HaShoeva.