Oil
Oil is a liquid derived from pressing olives. Oil is one of the seven liquids that make a fruit susceptible to tumah (ritual impurity).
In Chassidus, oil is analogous to the sefira of Chochma and the sefira of Chesed.
In Halacha
The use of oil follows general laws of kashrus.
Its Blessing
One who drinks olive oil alone does not make any blessing on it at all, since they derive no pleasure from drinking it and on the contrary, it is harmful to them.
If one drinks it with other beverages and the main purpose is drinking the oil (such as for medicinal purposes), they make the blessing "...borei pri ha'etz". The same applies to bread soaked in oil where there is no desire for the bread itself.
Oil is the only beverage that has this significance - that even after being pressed it retains the blessing of the fruit. For all other beverages, one makes the blessing "shehakol".
In Toras HaChassidus
Oil in general corresponds to the sefira of Chochma, however more specifically it refers to Chochma Stima'ah in Kesser which is the source of Chochma (which corresponds in a person to the intellect that is concealed from all thought). Therefore oil floats on water "even if the oil is initially below the water and water is placed on top of it, it will rise above the water" because water represents Chochma and the oil above it represents the source of Chochma.
However, in chapter 35 of Tanya it states that oil is an analogy not for Chochma but for mitzvos (and this forms the basis for all that follows there until the end of Tanya in chapter 53).
The Oil and Wine
Many times in Chassidus, oil and wine are mentioned as two types of avodah (divine service): avodah with hispaalus and hislahavus (excitement and enthusiasm) which is wine, connected more to the avodah of the Leviim, and avodah with bitul and quietly (oil) which is more connected to the avodah of the Kohanim.
In the Chamber of Oils in the Beis Hamikdash, many barrels containing wine and olive oil were permanently stored. This hints at the avodah of a Yid, which needs to contain both aspects - both wine and oil, meaning both hislahavus and bitul as one.
The reason that wine was also kept in the chamber is because a Yid's bitul should not be because they have no chayus and hislahavus in learning Torah chas v'shalom. However, despite this, we see that the chamber is called the Chamber of Oils specifically (and not the Chamber of Wine and Oil etc.), because the main emphasis is on the aspect of bitul.
The Oil as Fragrance-Giving
Oil is mentioned many times also as giving off fragrance to far distances. Therefore, oil is compared to the avodah of the Avos which was only in the aspect of fragrance and not a direct revelation of Hashem's light in the world. Meaning that in their avodah of fulfilling mitzvos they only drew down a divine illumination, and did not reach the level of fulfilling mitzvos as they are after Matan Torah, which contain the drawing down and revelation of His essence.
See Also
- Oil of non-Jews
- V'Atah Tetzaveh
Further reading
Torah Ohr D"H Vaatah Tetzavah