The Four Species are the following plants:
- the fruit of a citron tree – etrog אתרוג
- palm frond – lulav לולב
- myrtle twigs – hadass הדס
- willow twigs – aravah ערבה
The Four Species mitzvah requires holding the Four Species on each day of Sukkot. except Shabbat, reciting a blessing over them and waving them in all directions.
The source of this tradition is the commandment in Leviticus (23:40): “And you shall take for yourselves on the first day, the fruit of the hadar tree, date palm fronds, a branch of a braided tree, and willows of the brook, and you shall rejoice before the Lord your God for a seven day period.”
Our Sages claim that the Four Species represent the four types of people:
The etrog, that both tastes good and smells good stands for the Jews that study Torah and do good deeds.
The lulav, or rather the fruit of the tree of the lulav, tastes good but has no smell. It stands for those who study Torah but do not do good deeds.
The hadass has a good smell but no taste. It stands for those who do good deeds but do not study Torah.
The aravah that has neither taste nor smell stands for those who do not study Torah and don’t do good deeds.
In Sukkot they are bound together to symbolize that all Israel are bound together and serve as guarantors for one another.