This chapter contains three sections:
Our teacher the Beis Yosef writes:
“The second cup is drunk without a blessing before it or after it, since the blessing over wine (‘Borei Pri HaGafen”) is only said on the cup used for ‘Kiddush’ and Grace after Meals (‘Birchas Hamazone’). The blessing said after drinking wine (‘Al Hagefen’), is only said after the fourth cup”
Until here is the quote. He is of the opinion that the Hagadah and the accompanying praises are not considered an interruption [for the purposes of including all the cups under the same blessings]. Therefore, the blessing in Kiddush exempts the need for a blessing on the second cup, and the blessing on the third cup doubles as the cup of wine that accompanies Grace after Meals (‘Birchat Hamazone’), which also functions to exempt the fourth cup from a blessing.
Why doesn’t one say a blessing after the second cup? Because it is considered as ‘wine that precedes a meal, which exempts the wine during the meal from needing its own blessing [and is included in its scope]. Bircas Hamzone then comes to exempt the second cup from requiring a blessing afterward, as it usually does all year round, as I have written in chapter 174 (see the Baal HaMaor and Milchemes).
On the other hand, our teacher the Rema has this to say:
“The custom for the Ashkenazi Jews is to say a blessing before each cup. As for the blessing said afterward - the one after the fourth cup will suffice. This is also the opinion of the Gaonim.”
Until here is the quote. He point of view is that the Hagadah and its accompanying praises are considered interruptions. If this be so, why does he not require a blessing after the first and third cups of wine, since they are not connected? It would seem that he must also have the position that the Hagadah and praises are not interruptions, and if that is true, why do the first and fourth cups require a blessing before they are drunk?
The answer is that since the Rabbis enacted that the four cups cups be consumed in a manner displaying freedom, and each is a Mitzvah by itself, we do not allow these cups to be combined as ‘one period of drinking’, to be covered with one blessing. Rather, they are made to be separate displays, and each needs its own blessing (Magen Avraham).
Unfortunately, this answer is not completely satisfying. There are others who put forward that we consider ‘as if’ each cup was drunk under the condition that its blessing will only cover itself (Taz). This is even more of a wonder, for where do we find any evidence of such an implied condition?
In my humble understanding the following appears to me:
Note that the Maharil writes that:
“...a blessing need be made on each cup, even though the Rosh rules not to make a blessing. Tosfos writes that a blessing should be made, as it is prohibited to derive pleasure without one, and a doubt involving a prohibition always resolves towards a stricter ruling.”
Until here is the quote, and I don’t understand this all, as it is common knowledge that doubts of whether a blessing is required always are resolved toward the more lenient ruling. (The Chok Yaakov already raised this very question and was left perplexed by it, see there).
Therefore, it appears to me that this must be the explanation: Firstly, there is certainly a doubt in law as to whether the Hagadah is an interruption or not. That is why the previous chapter mentions that the size of Carpas to be eaten should not exceed an olive-size, and if it did a blessing should not be made over it afterward, since a doubt over a required blessing resolves to the lenient side, as I wrote there. Therefore, the result seen is that a blessing afterward should not be said [due to the doubt over whether the Hagadah is an interruption]. Now, if this is so, consider what is compelling the drinking of the cup of wine? If there is no external reason, the doubt in law [of the Hagadah’s interruption] can be resolved by not drinking. No drinking, no need for a blessing. So why does one have to drink and enter into complication? It is of course because he is forced to drink, due to the command of the Sages who instituted the four cups. If so, how could they say to a person ‘drink even though there may be a transgression in it’? He will retort ‘I do not wish to enter into a state of doubt over the prohibition deriving benefit without a blessing.’ What must be happening here is the Sages are saying ‘Drink and bless, and we will permit you to bless on our authority to enact Rabbinic laws. The result of all this is that the Rabbis’ enactment is not trying to exempt the second cup from the blessing before foods at all, and are allowing the blessing on their authority. However, when it comes to the blessing after the wine, the doubt that was always present remains, and the need for the blessing is nullified by the concept of ‘doubts regarding blessings are ruled leniently’.