Zevachim 110: Water Libation Origins

We learn a new Mishna again regarding prohibitions on services performed outside of the Temple courtyard.  Rabbi Elazar states that one who pours a water libation on the holiday of Sukkot outside of the Temple courtyard is liable for performing a Temple service incorrectly.

Steinsaltz teaches us more about the water libation services mentioned in Massechet Sukka (48). Water was taken from the Shiloach spring to the Temple accompanied by celebration.  The kohen would take the water up the ramp to the altar.  He would turn left and raise his hand while he poured the water into one of two bowls.  The second bowl was designated for the wine libation which happened with sacrifices other than those for Sukkot.  We are told that the priest raises his hand to prove that he poured the water properly and not on his feet, as one priest was pelted with etrogim for doing. 

The Gemara discusses where this tradition came from. Some believe that it was an interpretation of Bamidbar (29:31).  The Gemara suggests that the water libation practices were received at Mount Sinai, instructed through Moshe.  The rabbis argue about whether one method of learning the mitzvot is more valid than another.  Some believe that Torah law takes precedence, while others believe that even later rabbinic halacha is a form of G-d's word.