Berachos 8:1 - 8:2

אלו דברים – [According to the School of Shammai], he recites the blessing on the [Sabbath and/or Holy] Day – at the beginning the Sanctification of the Day and afterwards, recites the blessing on the wine, “Who creates the fruit of the vine/בורא פרי הגפן”, since he first sanctifies the day and afterwards the wine comes on the table because of the day – and just as he sanctified [the day] at its outset, similarly before the blessing of the wine (based upon the principle: "תדיר ושאינו תדיר, תדיר קודם"/"That which is more frequent vs. that which is less frequent, the more frequent comes first” – see Tractate Horayot, Chapter 3, Mishnah 6).

מברך על היין – [According to the School of Hillel, he recites the blessing on the wine] first, and the same applies to making Kiddush on the Bread (if he lacks fruit of the vine) since the wine or the bread cause [the need to] Sanctification of the Day, for if he doesn’t have wine or bread, he cannot recite the Sanctification/Kiddush.

בית שמאי אומרים: נוטלין לידים ואחר כך מוזגין את הכוס – For if you say “pour the cup” first, as a preventive measure, lest they defile the liquids that fell on the back of the cup on account of one’s hands, for hands prior to washing them are considered impure in the second-degree, and they defile liquids to become impure in the first-degree, and these liquids would come back and defile the outer surface of the cup, for the liquids that were defiled, defile utensils, according to the Rabbis, but they were lenient in this defilement for the utensil whose back was defiled by liquids [which] are impure, what is inside [the utensil] is not defiled nor one’s hands nor its (the utensil’s) rim. And the School of Shammai thinks that it is forbidden to use the cup whose back is impure, even though the inside was not defiled, as a preventive measure, lest splashing [of liquid] of drops from inside [the cup] touch the outer surface of the cup , and the liquids would acquire defilement on account of the outside of the cup, and would defile the hands, and since it is forbidden to use a utensil whose outside are impure, therefore, we wash our hands first and thereafter pour the cup [of wine], in order that the liquid on the outside of the utensil would not receive defilement on account of the hands – and the outside of the utensils would be found to be [ritually] impure, on account of those liquids and we would be using something that is in a forbidden state; but the School of Hillel thinks that there is no prohibition to use a utensil whose external parts are impure; therefore, we pour the cup [of wine] first and drink it and afterwards wash the hands, for if one would say that we wash the hands first and afterwards pour the cup, as a preventive measure lest the external parts of the cup would be impure, for it is permitted to handle a utensil whose external parts are impure, even if one’s hands are not dried well , which would defile the external parts of the utensil, the liquids on his hands and those liquids that had been made “first-degree” impure would defile the hands and it would be found that he would be eating with unclean hands.