הַשְׁקִיפָה֩ מִמְּע֨וֹן קָדְשְׁךָ֜ מִן־הַשָּׁמַ֗יִם וּבָרֵ֤ךְ אֶֽת־עַמְּךָ֙ אֶת־יִשְׂרָאֵ֔ל וְאֵת֙ הָאֲדָמָ֔ה אֲשֶׁ֥ר נָתַ֖תָּה לָ֑נוּ כַּאֲשֶׁ֤ר נִשְׁבַּ֙עְתָּ֙ לַאֲבֹתֵ֔ינוּ אֶ֛רֶץ זָבַ֥ת חָלָ֖ב וּדְבָֽשׁ׃ (ס)
Mira desde la morada de tu santidad, desde el cielo, y bendice á tu pueblo Israel, y á la tierra que nos has dado, como juraste á nuestros padres, tierra que fluye leche y miel.
Mishneh Torah, Blessings
Why does one not add "Amen" to the blessing one has said on partaking of fruit etc.? Because it is a single blessing, and Amen is only added to a final blessing, when preceded by one or more blessings; for example, the blessings recited by the King or the High Priest,*Mentioned in Mishnah Sotah, chapter I, paragraph 1 and set forth in detail in paragraphs 7 and 8. Paragraph 7:—Blessings recited after reading by the High Priest, or someone else, in his presence, during the night of the Day of Atonement, sections from the Book of Leviticus appertaining to the Day (Leviticus ch. 16 and ch. 23:26-32). Paragraph 8:—Blessings after recital in public of passages from the Book of Deuteronomy, on the second evening of the Feast of Tabernacles after the close of the Sabbatical year. This in accordance with the precept (Deuteronomy 31:10-13). The reading was done in the courtyard of the Temple on Mount Zion. The King was the Reader. If there was no King, the chief leader of the people was the reader. The passages read were Deuteronomy 1:1 till 6:9; 11:13 till 11:21; 14:22 till 14:29; 26:12 till 26:15, 17:15 till 17:20; chapter 28; and 17:15 till 17:20 were repeated. the addition of the Amen in these cases indicating that all the blessings had been completed.
Mishneh Torah, Prayer and the Priestly Blessing
In no place may the priests add, either softly or aloud, a blessing to the three verses of the Benediction, such as, "The Lord, the God of your fathers, make you a thousand times as many more as you are", or other verses of a similar tenor, for it is said, "Thou shalt not add to it" (Deuteronomy 13:1). Every priest proceeding to the platform to pronounce the Benediction, as soon as he starts, says, "May it be Thy Will, O Lord our God, that this Benediction which Thou hast commanded us to bless therewith Thy people Israel shall be a perfect blessing. May there be in it no stumbling nor perverseness from now and for evermore". Before the priest turns his face towards the people to bless them, he recites the blessing, "Blessed art Thou, O Lord our God, King of the Universe, who hast sanctified us with the sanctification of Aaron and commanded us to bless Thy people Israel with love". He then turns his face to the congregation and begins to bless them. And when he turns his face away from the congregation, after he had concluded the Benediction, he says "We have done that which Thou hast decreed unto us. Do Thou fulfill unto us that which Thou hast promised unto us. Do Thou look down from Thy holy habitation, from Heaven, and bless Thy People Israel".
Shulchan Arukh, Orach Chayim
Afterwards, the prayer leader begins [the blessing of] "Sim Shalom," and then the Kohanim turn their faces toward the ark, and they say: "Master of the Universe, we have done what You have decreed upon us; do what you have promised us: "Look forth from Your holy abode, from the Heavens, and bless Your people Israel..." (Deut. 26:15) Gloss: And they should elongate this prayer until the prayer leader concludes "Sim Shalom", so that the congregation answers "Amen" to both of them. But if they are not able to elongate [it] so much, they should say "Adir bamarom..." as stated below, siman 130. (Rashi - chapter "Eilu Ne'emarin" [Sotah, Chapter 7], and Hagahot Maimoni)