Lulav and Etrog
And you shall take for you on the first day, the fruit of the tree ‘hadar’ and branches of palm trees, and a bough of the tree avot and willows of the brook, and you shall rejoice before the Hashem, your G-d, seven days. Leviticus Chapter 23.
The mitzvah of taking the four species is for all seven days of Sukkot. Two blessings are said the first day, all netilat lulav and she’hecheeyanu and one bracha, al netilat lulav is said for the other six days. According to Torah law, the lulav is taken for all seven days only in the Holy Temple in Jerusalem when it was standing, and outside the Temple only on the first day of Sukkot. Our sages ordained, however, that we should also take the four species for all seven days as a remembrance of Temple Times.
The four species all taken together make up one single mitzvah. If any of the species are missing then you have not fulfilled the mitzvah at all. One lulav, one etrog, two aravot, and three hadasim is taken on Sukkot. The lulav, hadasim and aravot are bound together.
The four species are not taken on Shabbat even when it falls on the first day of Sukkot. The mitzvah applies during the day but not at night.
On the first day of Sukkot, a person must be careful to own the lulav and etrog he is performing the mitzvah with. On the the other six days, ownership is not strictly required.
A person should try to take four species, which are beautiful. Of course, this has to be done for the sake of the mitzvah and in service to G-d; not for the purpose of showing off to the neighbors.
"Origin of (the Four) Species"
The Biblical origin is in the Book of Vayikra; specifically, in Parshat Emor, where the Torah commands "And you shall take for yourselves on the First Day the fruit of a beautiful tree, the branches of date palms, branches of the myrtle tree, and branches of the willow tree, and you shall rejoice before Hashem, your G-d, for Seven Days." (Vayikra 23:40)
Symbolism of the Four Species
The Commandment is to take these four species together as a unit, and to shake them together in all directions, at various times on Sukkot.
One possible explanation is that we are taking these four elements from nature, and demonstrating that Hashem rules over nature everywhere and, by fulfilling this Command throughout the generations of our People, also at all times.
Two additional aspects of this "Group of Four" are as follows:
1. The "Etrog," the Citron, resembles in its shape, the heart, the driving force behind all our actions. The "Lulav," the Palm Branch, resembles the spine, which holds the body together and, without which, we would be unable to move. The "Hadasim," the Myrtle Branches, resemble, in their almond-shape, the eyes, with which we behold G-d's World. And the "Aravot," the Willow Branches, resemble the lips, with which we give expression to our thoughts and feelings.
By holding these four together, we show that a person should devote all of his-or- her strengths and capacities to the Service of Hashem.
2. The "Etrog" has both a pleasant taste and a pleasant aroma, symbolizing one who possesses both the blessings of knowledge of Torah and of good deeds. The "Lulav," the branch of a tree (the date palm) the fruit of which has good taste but no aroma, symbolizes the person who has Torah knowledge but not good deeds. The "Hadas," the myrtle, which has pleasant aroma only, symbolizes the person who has good deeds but not Torah. And the "Aravah," the willow branch, which has neither pleasant taste nor pleasant aroma, symbolizes the person who has neither Torah nor good deeds.
Holding these four in a tight bond represents the unity that is Hashem's goal for the Jewish People. The bond represents the conversion of a set of separate individuals into a People, which is far greater than any individual in both the Crown of Torah and the Crown of Good Deeds, and is far more deserving than any individual of the blessings of Hashem.
The Stolen (!) Four Species
For each of the Four Species, the Mishnah in Masechet Sukkah compares the stolen article to its dried out and lifeless form, which is absolutely invalid. This is derived from a word in the Torah, and is also very understandable. It is derived from the word "yourselves" in the expression "And you shall take for yourselves the fruit of a beautiful tree, …," implying that one's ownership is required."
But the explanation is to be found in the Talmud. The reason that the stolen "Lulav," for example, cannot be used as part of the fulfillment of a Divine Command, is that it would then be a "Command performed By Means of a Sin," which is self-contradictory! It is obvious that an Act would not be pleasing to Hashem, if it comes at the price of violation of one of His Own Commands.
Our Sages have said, in Masechet Shabbat (133) the following: The verse "This is my G-d and I will give Him Beauty," (Shemot 15:2) may be interpreted in this way …- (The Sages are offering a Midrashic explanation to answer the unasked question, "How can Man give anything to G-d?" Who was the Creator, and therefore Owner, of, literally, everything - and is the quintessential example of the difficulty of giving presents to one who has everything!)
"Make yourself beautiful before Him in your performance of the "Mitzvot," the Commandments: "… a beautiful "Sefer Torah," "Scroll of the Torah;" written for the sake of the Commandment, with beautiful ink, with a beautiful pen, by an expert scribe, and placed in a beautiful covering."
The above principle, of performing the Commandments in a beautiful way applies to all the (248) Positive "Mitzvot," or Commandments of the Torah, but has special application to the "Mitzvot" of Sukkot, where "beauty" is not just a quality describing the Commandment, but is an essential part of the Commandment. When the Torah describes an "Etrog," a Citron Fruit, as a "Pri Eitz Hadar," (Vayikra 23:40) a "fruit of a tree of beauty," it doesn't mean to say only that the fruit should exhibit the quality of beauty, but that beauty should be part of the essential nature of the "etrog."
To paraphrase Keats, with apologies, "Beauty is the "Etrog; the "Etrog," Beauty."
Keats had written, in "Ode on a Grecian Urn," the following:
"Beauty is Truth; Truth, Beauty
That is all ye know on earth,
And all ye need to know"
(which is somewhat doubtful).
In any case, this concept applies as well to all the "Mitzvot" of Sukkot, with lesser emphasis, perhaps, to the other members of the "four species," the four members of the fruit and plant "Kingdoms," which are used together as a "Mitzvah," but to the Sukkah, itself, as well.
That is why we go to such effort to beautify our Sukkot; to hang pleasant fruit and vegetables, real or imitation, fancy decorative hangings, pictures on the walls of the Land of Israel, of scenes from Jewish History, especially of Times of the Temple, verses from the Bible, portraits of great Jewish Leaders from ancient and less ancient times. It is why we use our best dishes and silverware, glasses and Kiddush Cups; to live in the "Sukkah," on a temporary basis, in the same manner as we live in our "permanent and secure" homes all year long.