וְעַתָּ֗ה הוֹאֵל֙ וּבָרֵךְ֙ אֶת־בֵּ֣ית עַבְדְּךָ֔ לִהְי֥וֹת לְעוֹלָ֖ם לְפָנֶ֑יךָ כִּֽי־אַתָּ֞ה אֲדֹנָ֤י יְהוִה֙ דִּבַּ֔רְתָּ וּמִבִּרְכָ֣תְךָ֔ יְבֹרַ֥ךְ בֵּֽית־עַבְדְּךָ֖ לְעוֹלָֽם׃ (פ)
At ngayon, nawa'y kalugdan Mong pagpalain ang sambahayan ng Iyong lingkod, upang manatili ito magpakailanman sa harap Mo; sapagkat Ikaw, Panginoong Walang-Hanggan, ang nagsalita nito, at sa pamamagitan ng Iyong pagpapala ay pagpapalain ang sambahayan ng Iyong lingkod magpakailanman.
Ein Yaakov
How does one invite [others to recite a blessing]? With three [people], one says "let us bless [God]". With three and himself, he says "bless [God]". Gemara: Shmuel said, "A person should never exclude himself from the community
Ein Yaakov
Translation: What is the law regarding the blessings of a non-Jew, whether he is a Torah scholar or not? Rabbi says: "If he blesses with enthusiasm, he is a Torah scholar, and if not, he is an ignoramus." Abaye said to Rav Dimi: "But isn't it written (in 2 Samuel 7:29), 'And may Your house be blessed forever from Your blessing'? This is a question." Likewise, in another verse (in Psalm 81:11), it is written, "Open your mouth wide, and I will fill it." This one is written in matters of Torah.
Midrash Tanchuma Buber
[(Numb. 6:23:) THUS SHALL YOU BLESS.] This text is related (to Deut. 26:15): LOOK DOWN FROM YOUR HOLY DWELLING, FROM THE HEAVENS, AND BLESS YOUR PEOPLE. And in the same vein David says (in II Sam. 7:29): SO NOW MAY YOU BE PLEASED TO BLESS YOUR SERVANT'S HOUSE, THAT IT ABIDE BEFORE YOU FOREVER…. AND MAY YOUR SERVANT's HOUSE BE BLESSED FOR EVER WITH YOUR BLESSING{S}. The congregation of Israel said to the Holy One: Sovereign of the World, you tell your priests to bless us.58Tanh., Numb. 2:8, cont.; Numb. R. 11:2. We only need you to bless us. (Deut. 26:15): LOOK DOWN FROM YOUR HOLY DWELLING, FROM THE HEAVENS, <AND BLESS YOUR PEOPLE>. The Holy One said to them: Although I have told the priests to bless you, I am standing along with them and blessing you. For that reason the priests spread their hands.59See Sot. 7:6 for details about how the priests were to hold their hands. <They do so> to say: The Holy One is standing behind us. So also it says (with reference to the Holy One in Cant. 2:9) THERE HE STANDS BEHIND OUR WALL, GAZING THROUGH THE WINDOWS, PEERING THROUGH THE LATTICE, <i.e.> GAZING THROUGH THE WINDOWS, from between the fingers of the priests; PEERING THROUGH THE LATTICE, when they extend their hands. It is therefore stated (in Numb. 6:23:) THUS SHALL YOU BLESS.