The Midrash (Vayikra Rabba 30) offers the following parable to explain why one may not use a stolen lulav on Sukkos: A highway robber once stopped a high-ranking official and robbed him of everything he had. One day the robber was caught and brought to trial before the king. The official heard that the bandit had been caught and went to tell the prisoner that each person brought to trial is allowed to bring someone to speak on his behalf. The official told the thief that he should request that he, the official, speak for him.
The thief took his advice and did so. Yet, when the official got up to speak, he informed the court of all the horrible things the highwayman did to him. The Midrash concludes: Woe is to him whose defendant becomes his prosecutor.
In what way is our lulav considered our defendant? And how does it become a prosecutor if one uses a stolen one?
Perhaps we can answer these questions with the following parable about Tishrei that the Midrash offers further in the same perek: A certain city owed a hefty tax, and the ruler was en route to collect it. The elders of the city came to greet the king 10 miles before he reached the city and praised him. In response, the king reduced a third of the owed tax. When the king reached within five miles of the city, the city’s middle-class went out to greet him and sing his praises. In response, the king forgave another third of the tax. When the king finally entered the city, every single person came out to greet and praise him, whereupon he forgave the entire sum.
The Midrash explains that before Rosh Hashanah, tzaddikim fast and Hashem forgives a third of our aveiros. From Rosh Hashanah through Yom Kippur, many more individuals fast and another third of our aveiros are forgiven. Then, on Yom Kippur, everyone fasts and from Yom Kippur through Sukkos every person is busy with mitzvos – this one with his sukkah, this one with his lulav, etc. Thus, on the first day of Sukkos, when we each stand before Hashem with our lulavim in our hands, Hashem says, “I forgive all of their averos.”
The Midrash concludes that this explains why Moshe Rabbeinu warned us: “V’lakachtem lachem bayom harishon – And you shall take for yourselves [the four species],” which teaches that we cannot use a stolen lulav on Sukkos. Since the mitzvah of lulav is connected to the process of forgiveness of Yom Kippur, we should not use a stolen lulav as we would effectively be calling our prosecutor to come to our defense.
May we all merit that our aveiros indeed be forgiven, leading to the ultimate simcha on yom tov. Amen.