Gemara

Rav Mesharshiya brei d'Rav Noson: Hillel had a tradition that after the Churban one should not eat Matzah and Maror wrapped together. Since Matzah is a Mitzvah mid'Oraisa and Maror is only mid'Rabanan, Maror is Mevatel Matzah.

Even the opinion that Mitzvos do not Mevatel each other says this only when both are mid'Oraisa or both are mid'Rabanan. However, if one is mid'Oraisa and the other is mid'Rabanan, the mid'Rabanan is Mevatel the mid'Oraisa.

Question: Who says that Mitzvos do not Mevatel each other?

Answer: Hillel says so. He used to wrap them (Pesach, Matzah and Maror) together and eat them to fulfill "Al Matzos u'Morerim Yochluhu".

Question: Surely, a k'Zayis of each is required - but one cannot swallow more than two k'Zeisim at a time (Kerisus 14a)!

Answer (Mordechai 38b DH Korchan): He puts a k'Zayis of each in his mouth. They get mashed during chewing to the size of an egg (or less), and one can swallow them at once.

R. Yochanan: Hillel's colleagues disagree:

(Beraisa) Suggestion: Perhaps one wraps them together and eats them like Hillel did!

Rejection: "Al Matzos u'Morerim Yochluhu" (it could have said 'Yochlu' - rather, it says Yochluhu, we read this 'Yochal Hu'), one may even eat each by itself.

Objection (Rav Ashi): If so, why does it say even?

Answer (Rav Ashi): Rather, the Beraisa means as follows:

Suggestion: Perhaps one must wrap them together like Hillel did to be Yotzei!

Rejection: "Al Matzos u'Morerim Yochluhu" - one may even eat each by itself.

Conclusion: The Halachah was not fixed like Hillel, nor like Chachamim - [nowadays] we bless Al Achilas Matzah, eat Matzah, bless Al Achilas Maror, eat Maror, and then eat Korech (both wrapped together) without a Berachah, to commemorate when there is a Mikdash, according to Hillel.

Rav Papa: One should not leave the Charoses on the Maror, lest its sweetness (it is made with apples) blunt the bitterness of the Maror (one must taste Maror to be Yotzei).

Rishonim

Rif and Rosh (10:27): Hillel taught that nowadays, if one eats Matzah and Maror wrapped together, Maror is Mevatel Matzah. All agree that a Mitzvah mid'Rabanan is Mevatel a Mitzvah mid'Oraisa.

R. Yochanan: Hillel used to wrap them together and eat them to fulfill "Al Matzos u'Morerim Yochluhu"; his colleagues disagree.

(Beraisa) Suggestion: Perhaps one is not Yotzei unless he wraps them together and eats them like Hillel did!

Rejection: "Al Matzos u'Morerim Yochluhu", one may even eat each by itself.

Conclusion: The Halachah was not fixed like Hillel, nor like Chachamim. Nowadays we want to eat both together, to recall the Mikdash; we also must eat each by itself, for otherwise Maror mid'Rabanan would Mevatel Matzah mid'Oraisa! First one blesses Al Achilas Matzah and eats Matzah, tThen he blesses Al Achilas Maror and eats Maror, then he eats both together without a Berachah, to commemorate the Mikdash according to Hillel.

Question (Ba'al ha'Ma'or): The Rif says that the Beraisa proves R. Yochanan's assertion that Chachamim argue with Hillel. But the conclusion was like Rav Ashi, that the Beraisa is like Hillel! It teaches that one need not eat them wrapped together, but one may do so! Rather, R. Yochanan must have had a tradition that Chachamim argue with Hillel.

Answer (Milchamos Hash-m): In the Ba'al ha'Ma'or's text, Rav Ashi explicitly establishes the Beraisa like Hillel. However, the correct text does not. It cannot be like Hillel, for it says 'perhaps one must do like Hillel used to do'. According to Hillel, this is how the Torah requires! Rav Ashi does not argue with R. Yochanan. Rather, he refutes the Gemara's assertion that there is an opinion that Mitzvos (mid'Oraisa) Mevatel each other. The Beraisa is like Chachamim, and they agree that one is Yotzei by eating them together! They argue only about whether or not the verse requires eating them together.

Question: Perhaps Hillel holds that normally Mitzvos Mevatel each other; here is different, because the Torah commanded to eat them together! Chachamim hold that Mitzvos Mevatel each other, yet they agree that if one ate them together he was Yotzei!

Answer (Tosfos): If Hillel held that normally Mitzvos Mevatel each other, he would need the verse to permit eating them together, he would have no source to require this l'Chatchilah.

Rosh (ibid.): We dip Korech in Charoses, for this is the only time Hillel would dip in Charoses.

Question: The Gemara implies that had the Halachah been fixed like either opinion, we would act differently. But this is not so! Hillel agrees that nowadays we cannot eat them together, for Maror would Mevatel Matzah!

Answer (Rosh ibid.): If the Halachah would be like Hillel, we would bless on Matzah and eat it, then bless on Maror and eat it with Matzah. Since Maror and Korech are both mid'Rabanan, they do not Mevatel each other.

Question: If (according to the Rif) Chachamim agree that equal Mitzvos do not Mevatel each other, we should be able to do so according to everyone! Why must we eat Maror by itself?

Answer (Rosh ibid. and Milchamos Hash-m): Perhaps the Halachah follows Chachamim; they hold that Korech is Reshus (not a Mitzvah at all), it would be Mevatel Maror (a Mitzvah mid'Rabanan), just like a mid'Rabanan is Mevatel a mid'Oraisa.

Rambam (Hilchos Chametz u'Matzah 8:6): One takes two Matzos, breaks one, puts the piece inside the whole Matzah and blesses ha'Motzi. Afterwards he wraps Matzah and Maror together and blesses 'Al Achilas Matzos u'Morerim' and eats them. If he ate each of them by itself he blesses on each of them by itself.

Magid Mishnah: This is when there is a Mikdash, and Matzah and Maror are both mid'Oraisa, so neither is Mevatel the other.

Question (Lechem Mishneh): Since the Gemara said that the Halachah was not decided like Hillel or Chachamim, we should be stringent to eat both ways! Also, to be concerned for Hillel, the Pesach must also be eaten with them!

Answer (Griz Zevachim 79a DH bi'Gemara k'Shem): The Rambam holds that Korech consisted only of Matzah and Maror.

Note: The Gemara says that Hillel wrapped them together; it does not specify whether or not this includes the Pesach. It says "Al Matzos u'Merorim Yochluhu"; R. Yochanan (Pesachim 63b) holds that 'Al' does not connote nearby. Also, perhaps the Mordechai's question above bothered the Rambam, and he did not accept the answer because he holds that one must swallow a k'Zayis of each. The Yerushalmi (Chalah 2b) explicitly says that Hillel ate all three together. However, the Yerushalmi was forced to say so because it holds (unlike the Bavli) that Bitul applies only if there are at least three things.

Rambam (ibid. 8:8): Nowadays one blesses ha'Motzi and Al Achilas Matzah, dips the Matzah in Charoses and eats it. Then he blesses Al Achilas Maror, dips the Maror in Charoses but does not leave it in very long, and eats it. This is a Mitzvah mid'Rabanan.

R. Mano'ach (DH v'Lo): Even though it is a Mitzvah mid'Rabanan to dip in Charoses, since the Torah mentions Maror but not Charoses, Maror is like mid'Oraisa compared to Charoses. Therefore, the Charoses would Mevatel the Maror if the Maror was left in for a while. We are not concerned lest Charoses Mevatel the Matzah because one need not taste the Matzah. Alternatively, Matzah is dry and it does not absorb much taste.

Question: If Matzah is made from rice and grain, we do not say that rice of Reshus is Mevatel grain of Mitzvah (Zevachim 78a)!

Answer #1 (R. David DH v'Ifshar): We are concerned lest there will be enough Maror to Mevatel the taste of Matzah. Alternatively, perhaps the Maror will be a Chatzitzah between the Matzah and his throat.

Answer #2 (R. David ibid. and Tosfos Zevachim 78a DH Ela): Maror is Mevatel Matzah, for its taste is potent. Alternatively, Maror is Mevatel some taste of the k'Zayis of Matzah; if the Korech contains a larger Shi'ur of Matzah, one is Yotzei.

Question (Gilyon ha'Shas Zevachim ibid.): Nowadays, after eating Matzah by itself we eat Maror by itself. We do not eat it with Matzah, for then Matzah is Reshus and it would Mevatel Maror, even though Matzah's taste is not potent!

Answer #1: Keren Orah (Zevachim 78a DH v'Ein): Chachamim hold that Mitzvos Mevatel each other. Regarding Min b'Mino, the minority is Batel, one was not Yotzei that Mitzvah. Regarding Min b'Eino Mino, if each can be tasted neither is Batel. However, l'Chatchilah they should be eaten separately.

Answer #2 (Magihah in R. David, 19): Since there is a Mitzvah to taste the Maror, we are concerned even for a slight blunting of its taste.

Answer #3 (Maharam Chalavah citing Ramban): Here, we do not discuss Bitul of taste. Rather, it was enacted to do each Mitzvah by itself.

To answer Question (ii) the Ramban can say that Matzah made of rice and grain is one entity (they were mixed before it received the name Matzah, at the time of baking), so it is considered doing the Mitzvah by itself.

Griz (Zevachim ibid.): We are concerned for Bitul of the Mitzvah, not of the taste! Nevertheless, if one can taste the Matzah he is Yotzei because Ta'am k'Ikar.

Question Griz (ibid.): In Zevachim, Rashi says that Hillel teaches that we are not concerned lest Maror Mevatel the taste of Matzah. Why doesn't he address Bitul of the Pesach? Rashi holds that Pesach is eaten together with Matzah and Maror!

Note: Rashba (Berachos 38b DH Lo) proves from the law of Bitul that we require the taste of Matzah. Perhaps Rashi holds that we learn from a Hekesh to Maror (reason dictates that taste of Maror is required), but we do not require the taste of Pesach. Alternatively, he teaches that Maror is not Mevatel Matzah, and all the more so it is not Mevatel Pesach, for meat has a more potent taste than Matzah.

Poskim

Shulchan Aruch (OC 475 1): One holds together the three Matzos with the broken one in the middle, blesses ha'Motzi and Al Achilas Matzah...and eats a k'Zayis from each.

Magen Avraham (4): One should put a k'Zayis of each in his mouth at once, but it suffices to swallow a k'Zayis at once. (We learn from the Mordechai cited above (a:4:ii).) B'Di'eved, even if a k'Zayis was swallowed within Kdei Achilas Pras he was Yotzei. If it is hard to swallow a k'Zayis of Maror at once, l'Chatchilah one may swallow it within Kdei Achilas Pras.

Afterwards he fully submerges a k'Zayis of Maror in Charoses but does not leave it in very long, lest it lose its bitterness. For this reason one must shake the Charoses off. He blesses Al Achilas Maror and eats it without reclining. Afterwards he cuts the bottom Matzah and wraps a piece together with Maror and dips them in Charoses.

Rema: Some say not to dip them; this is our custom.

Hagahos Maimoniyos (Hilchos Chametz u'Matzah 8:7): The first opinion holds that we dip Korech in Charoses like Hillel used to. The latter opinion holds that we dip in Charoses to counter Kapa (a worm or venom), and there is no concern for Kapa regarding anything eaten with bread (Yerushalmi).

Shulchan Aruch (ibid.): He says 'Zecher l'Mikdash, according to Hillel' and eats them together while reclining.

Magen Avraham (8): If it is not difficult, one should swallow both k'Zeisim together.

Shulchan Aruch (ibid.): From the time he blesses Al Achilas Matzah he should not talk about matters unrelated to the meal until Korech, in order that the Berachos of Al Achilas Matzah and Al Achilas Maror will also apply to Korech.

Taz (7): We are concerned for Hillel's opinion; Hillel holds that one is not Yotzei until Korech.

Mishbetzos Zahav (7): The Bach says that when there is no Pesach, there is no Mitzvah of Korech even mid'Rabanan, it is a mere commemoration. This is like Rashi. However, Tosfos holds that according to Hillel it is a Mitzvah mid'Rabanan.

Question: Since it is a Safek (whom the Halachah follows) regarding a mid'Rabanan, it should suffice to fulfill one opinion, especially since Hillel agrees that one is Yotzei b'Di'eved by eating each by itself (according to Ba'al ha'Ma'or).

Answer (Mishbetzos Zahav ibid.): Indeed, we hold that the Halachah follows Hillel; we are merely stringent to also be concerned for Chachamim.

Bi'ur Halachah (v'Omer): Presumably, the Mechaber does not mean that one should say 'Zecher l'Mikdash...' before beginning to eat it, for this is a Hefsek!

Kaf ha'Chayim (8,19): One should intend that Al Achilas Matzah also apply to the Afikoman. As long as one began to eat before talking, he need not repeat the Berachah even if he talked before finishing a k'Zayis.