Talmud for Zevachim 220:5
אמר ליה ריש לקיש לר' יוחנן אי מה להלן שלשת לוגין אף כאן שלשת לוגין והא ר"א מי החג קאמר אי מה להלן בשאר ימות השנה אף כאן בשאר ימות השנה [ור"א] בחג קאמר
R'Eleazar ruled thus in accordance with the thesis of R'Akiba, his teacher, who maintained [that] the pouring of water [on the Feast of Tabernacles] is [required] by Scriptural law, For it was taught: R'Akiba said: And the drink-offerings thereof:<span class="x" onmousemove="('comment',' Num. XXIX, 31. This refers to the drinkofferings which accompanied the animal sacrifices on Tabernacles, R. Akiba stresses the plural 'offerings'.');"><sup>6</sup></span> Scripture speaks of two drink-offerings, viz. , the libation of water and the libation of wine.<span class="x" onmousemove="('comment',' Hence it is Scriptural, and since it is a Scriptural rite, one is liable for doing it without.');"><sup>7</sup></span>