כוס של ברכה טעון הדחה מבפנים ושטיפה מבחוץ ואם הוא נקי ואין בו שיורי כוסות אינו צריך:

One who blesses, how he should conduct himself with the cup of Birkat Hamazon. Containing 12 paragraphs.

1. The cup of blessing for the Birkat HaMazon requires washing on the inside and rinsing on the outside. And if it was clean without residue on the cups, the rinsing and washing are not necessary.

2. The wine should be placed within the cup undiluted until reaching the Blessing of The Land, and then the wine should be mixed to acknowledge the praise of the land. Rem"a And there are some who say that if the wine is not strong, we need not dilute it with water [Tur]. And this how we are accustomed in these lands. And we take it out from the barrel for the purpose of a blessing [Tur in the name of Rashi]. And it seems for us that we only need to pour it from the jug that we guard of it wine for the purpose of a blessing; and it need not exactly be from a barrel. And this is how we are accustomed in these countries. And the cup for blessing should be filled up to the rim.

3. One needs to seek out a full cup [of wine] [for blessing over the Birkat HaMazon]

4. One receives the cup of blessing with two hands, and, when one begins blessing, one should lift it up with one's right hand without assisting it with one's left hand. Rema: And this [practice to not use one's left hand in elevating the cup of blessing] is specifically so that the left hand should not touch the cup; but, if one places the left hand beneath the right hand to help it, that is permissible. [Beis Yosef, in the name of the Shevulei HaLeket] And one should elevate it a fistbreadth from the ground if one was sitting on the ground. And if one was lounging at a table, one elevates it above the table a fistbreadth. And one sets one's eyes upon it, so as not to lose mindfulness about it. Rem"a: And, therefore [since one should place one's eyes upon the cup], one should not buy a cup - called a glueck - whose lip is thin, to bless upon it. And he sends it to one's wife so that she should drink from it.

5. There is one who says that if the blesser is lefthanded, the blesser should grab the cup in the blesser's right hand, which is everybody's left hand.

6. From when the cup is given to him to bless, the one blessing should not speak, and those reclining at the meal should not speak from the moment the one blessing begins. Not only while he is actually blessing — when they must listen and understand what the one blessing says — but even between one blessing and the next they should not speak. And if they transgressed and spoke between blessing and blessing, at a time when the one blessing was momentarily silent, they have fulfilled their obligation. (Rema): Even if the one blessing himself spoke. But if they spoke while he was actually blessing, they have not fulfilled their obligation.

7. It is proper that each of those reclining at the meal should recite quietly along with the one blessing every single blessing, and even the concluding formulas. (Rema): And he should finish slightly before the one blessing, so that he can answer Amen, as above in Siman 59. One does not give the cup of blessing except to one with a generous eye [Gemara, chapter Elu Ne'emarin].

8. Regarding interrupting Birkat Hamazon to inquire out of fear or out of honor, there is one who says that its law is like that of Tefillah.

9. One must sit at the time of blessing. Whether he was walking about his house when he ate, or standing, or reclining — when he reaches the point of blessing he must sit, so that he can concentrate better, and also so that he will not be reclining, which is a manner of haughtiness. Rather he should sit with awe. Rema: It appears to me that this is not specifically regarding the one blessing, but rather the same applies to all those reclining at the meal — they should not sit with levity but rather with awe. However, if they did not do so, even if he blessed while walking, after the fact he has fulfilled his obligation [Rambam, Chapter 4].

10. Some say that even al hamichya must be recited while sitting.

11. If one was walking and eating he does not need to sit to recite the beracha since his mind will not be settled.

12. It is forbidden to recite birkas hamazon while engaged in another activity.