Rabbi Aryeh Lebowitz

The Kezias that you're doing for your Seudah, that's independent.

You don't need a Seba for that.

Haseba is only an ofen kiyu mitzvah salayla.

It's the way to do the mitzvah salayla.

So it's not a kasha at all what the Bir Alecha says.

Why doesn't the Gemara mention about two kezesim?

Gemara is only talking about Haseba.

It's not going to talk about shenei kezesim.

That's what Rav Shachter writes in Osir.

It's good to see also Osir Aleph over there what he says in explaining the Shitas HaRambam.

But we'll leave that aside for now.

Now why is it

Now, first of all, this is not why, this is not accepted by everybody, that you need to have Shnei Kezesim.

The Mishabur writes in Ziv Kot Niralv, certainly B'di Yeved, if you eat only one Kezais, you're certainly Yotzei.

In Orchos Rabbeinu Chalek Beis, page Samach Tes, they quote from the Stipler that it's a Chumra G'dola to require Shnei Kezesim, and he says that the Chazanish, his brother-in-law, the Chazanish, Zecher Tzadik V'Kadosh Levracha, Ochal Rak Kezai Zecher.

Now,

it was a chas nish kazayis, but it was a kazayis echad.

So maybe what would be by us, shnei kazayisim, but he ate only one kazayis, he thought that it was a chumra gedola.

Now there's an additional chumra, not just to eat shnei kazayisim, but to eat shnei kazayisim biyachad.

To swallow shnei kazayisim, have them both in your mouth at the same time, to eat them both together.