Some Halachot that will apply to the 1st night of Rosh Hashana. This law would apply on the 1st night of Rosh Hashana on any given year. The 1st Mitzvah of the new year, every year, is the Berachot of Kriyat Shema in Arbit. That’s the 1st Mitzvah you are going to fulfill in the new year.
Therefore the Mate Efrayim brings down how extra careful you should be during the 1st Kriyat Shema of the year. He says to read it extra slow, and to read it with extra pronunciation and clarity. That’s because, like most of the things we do on Rosh Hashana, we do it in order as an omen or representation of the year to come. So certainly, the 1st Mitzvah we do, which is a Mitzvah from the Torah, will set the pace for all the Mitzvot we are going to do for the coming year. So therefore the Mate Efrayim brings down, while of course one has to be careful with every single Kriyat Shema throughout the year, however, one should be extra careful when it comes to the 1st Kriyat Shema on the night of Rosh Hashana. That’s in order that it will set a good sign that all your Mitzvot will be done with precision as such throughout the whole year.
This year happens to be that Rosh Hashana is on a Friday night. So after Amidat Arbit, the Birkat Me’en Sheva will be said just like it is said on every Friday night. But it should be pointed out that instead of saying in the text, ‘HaEl HaKadosh She’en Kamohu’, one has to change that to ‘HaMelech HaKadosh’. It’s just like we change HaMelech in the Amida, so we change it also in the Birkat Me’en Sheva.
There’s actually a great Machloket (argument) amongst the Acharonim, regarding if one makes a mistake in the Birkat Mehen Sheva. The mistake being if instead of saying HaMelech, he says ‘HaEl HaKadosh’. So, it is the opinion of Rav Chida that if one makes a mistake, you go back. He writes such, because the Inyan (issue) of this Beracha that we are saying has very deep significance not only according to he Peshat (literal meaning), but according to the Kabala, and therefore if one makes a mistake on it, it affects the mysticism behind it, and therefore one has to go back. However, the opinion of the Peri Chadash is that one does not have to go back. The whole reason why we are saying this Beracha is really for Friday night HaMelech HaKadosh is a Rosh Hashana item. So since the mistake was not in the Shabbat item, but was in the Rosh Hashana item, and the Me’en Sheva comes because of Shabbat, so therefore there’s a strong logic to say that you don’t have to go back if you made a mistake.
The Halacha therefore is, since already we have a Machloket in this subject, we will say ‘Safek Berachot Lehakel’ (being that it’s from the Derabanan [Rabbis], as opposed from The Torah, so we are lenient with it’s strictness in order not to say Hashem’s name in vain). But, if one remembers before he finished Baruch Ata Hashem Mekadesh HaShabbat, then of course he should go back and say HaMelech HaKadosh. (We are talking about the Chazan.) However, if already he said Baruch Ata Hashem Mekadesh HaShabbat, and then he realizes he only said HaEl HaKadosh, the Halacha we will say ‘Safek Berachot Lehakhel’ and you do not have to go back.