Read the priestly blessing with the verses both before and after the three part blessing.
What questions arise for you?
Are the KOHANIM the actual ones giving the blessing or are they DESCRIBING the blessing that God will ultimately give?
(כב) וַיְדַבֵּ֥ר יְהוָ֖ה אֶל־מֹשֶׁ֥ה לֵּאמֹֽר׃
(כג) דַּבֵּ֤ר אֶֽל־אַהֲרֹן֙ וְאֶל־בָּנָ֣יו לֵאמֹ֔ר כֹּ֥ה תְבָרֲכ֖וּ אֶת־בְּנֵ֣י יִשְׂרָאֵ֑ל אָמ֖וֹר לָהֶֽם׃ (ס)
(כד) יְבָרֶכְךָ֥ יְהוָ֖ה וְיִשְׁמְרֶֽךָ׃ (ס)
(כה) יָאֵ֨ר יְהוָ֧ה ׀ פָּנָ֛יו אֵלֶ֖יךָ וִֽיחֻנֶּֽךָּ׃ (ס)
(כו) יִשָּׂ֨א יְהוָ֤ה ׀ פָּנָיו֙ אֵלֶ֔יךָ וְיָשֵׂ֥ם לְךָ֖ שָׁלֽוֹם׃ (ס)
(כז) וְשָׂמ֥וּ אֶת־שְׁמִ֖י עַל־בְּנֵ֣י יִשְׂרָאֵ֑ל וַאֲנִ֖י אֲבָרֲכֵֽם׃
(22) The Eternal spoke to Moses: (23) Speak to Aaron and his sons: Thus shall you bless the people of Israel. Say to them:
(24) May the Holy One bless you and protect you!
(25) May God shine His face upon you (or does it mean deal kindly?) and be gracious with you!
(26) May God lift the Divine Face toward you (does it mean bestow favour upon you?) and grant you peace!
(27) Thus they shall link My name with the people of Israel, and I, I will bless them.
Read this Rashi - What is God's job according to this commentary?
The Priestly Blessing from the Biblical Age - The Oldest Biblical Text We Have in Our Possession

It is very, very old.
An archaeological find in a burial chamber in Ketef Hinnom (South of the Old City of Jerusalem) in 1979 shows that this blessing goes at least as far back as the 7th century BCE when the 1st Temple still stood and before the Babylonian exile.
Two tiny folded silver scrolls with different versions of this blessing and some other fragments of verses were discovered, each including the words “May YHWH bless you and guard you; may YHWH make his face shine upon you.”
This is the oldest text ever found, that occurs in the Hebrew Bible.
Were the scrolls used as amulets by ancient Israelites more than 2,600 years ago? Were they kept in the ancient ark in a decorated case? in pottery? Were they rolled and unrolled and placed on worshippers arms? heads? between their eyes? We can only imagine given the other ancient texts and preserved traditions.
Do the Jews deserve a special blessing?!
THE MEANING OF THE BLESSING
Accordingly, the three sections of the priestly benedictions illustrate an ascending order, starting with a blessing concerned with man’s material needs and then dealing with his spiritual wants, and finally reaching a climax combining both these factors together, crowning them with the blessing of peace. This ascending order and increasing surge of blessing is reflected in the language and rhythm.
Studies in Bemidbar, Nehama Leibowitz, p. 67
Part of the blessing’s power lies in the simplicity of its structure, which Bible scholar Jacob Milgrom describes as “a rising crescendo”: There are three words in the first line, five in the second, and seven in the third; fifteen consonants in the first line, twenty in the second, and twenty five in the third. The sense conveyed is of increasing, overflowing divine blessing.
(Bamidbar 6:24) "The L-rd bless you": with the explicit blessing (Devarim 28:3-6) "Blessed shall you be in the city and blessed shall you be in the field … Blessed shall be your basket and your remainder. Blessed shall you be in your coming in and blessed shall you be in your going out." "The L-rd bless you": with possessions "and keep you": with possessions. R. Nathan says: May He bless you with possessions and keep you — in body. R. Yitzchak says "and keep you": from the evil inclination, as it is written (Proverbs 3:26) "For the L-rd will be with you in your trust, and He will guard your feet from entrapment." Variantly: "and keep you": from all evil, viz. (Psalms 121:4-7) "He neither slumbers nor sleeps, the Keeper of Israel … at your right hand … By day the sun … The L-rd will keep you from all evil." Variantly: "and keep you": from mazikkin (destructive agents), viz. (Ibid. 91:11) "For His angels will He charge for you to keep you in all your ways." Variantly: "and keep you": He will keep for you the covenant of your fathers, viz. (Devarim 7:12) "… then the L-rd your G-d will keep for you the covenant and the lovingkindness which He swore to your fathers." Variantly: "and keep you": He will keep for you the "end" (i.e., the time of redemption). And thus is it written (Isaiah 21:11-12) "A prophecy concerning Duma (Edom): He (Israel) calls to Me from Seir: 'Keeper, what of the night?' 'Keeper, what of the night?' The Keeper says: 'Morning is coming and also night, etc.'" Variantly: "and keep you": He will keep your soul at the time of death, viz. (I Samuel 25:29) "and my master's soul will be bound up (after death) in the bond of life." From this I would understand both (the soul of) the righteous and the wicked to be intended. It is, therefore, written (Ibid.) "but the soul of your foes will He hurl away from the hollow of a sling." Variantly: "and keep you": He will keep your feet from Gehinnom, viz.: (Ibid. 2:9) "He will keep (from Gehennom) the feet of His pious ones." Variantly: "and keep you": He will keep you in the world to come, viz. (Isaiah 4:31) "But those who trust in the L-rd will renew strength. They will lift their wings as eagles, etc."
אמור להם
שֶׁיִּהְיוּ כֻלָּם שׁוֹמְעִים
Saying Unto Them (Rashi)
so that all of them should hear the blessing
It does not suffice to pronounce the
blessings upon the Israelites in their absence
(Sifrei BaMidbar 39)
THE BLESSING OF THE KOHANIM IN SYNAGOGUE
אין נשיאת כפים פחות מי' והכהנים מהמנין: ואין לזר לישא כפיו אפילו עם (כהנים אחרים) (בפ' ב' דכתובות דכ"ד דזר עובר בעשה) (ותו' פ' כל כתבי לא ידע ר"י מה איסור יש בזר העולה ואפשר דעם כהנים אחרים וצ"ע):
Birkat Kohanim is not performed if there are fewer than ten, including the Kohanim in the quorum. Ram"a: A non-kohen should not perform Birkat Kohanim, even if there are other kohanim present (Ketubot, ch. 2, daf 24, states that a non-kohen violates a positive commandment; but Tosafot in the chapter "Kol Kitvei" (Tr. Shabbat) states that R"i does not know what prohibition there would be for a non-kohen who ascends [for Birkat Kohanim], and it is possible that with other kohanim it would be permitted; but this requires further consideration).
ברוך אתה יי אלהינו מלך העולם אשר קדשנו בקדושתו של אהרון וצונו לברך את עמו ישראל באהבה
Before the Priests bless they say, "Blessed are You, Eternal our God, Ruler of the universe, who has sanctified us with the sanctity of Aaron and commanded us to bless Your people Israel with love."
In Israel this blessing is recited daily at shacharit (and at mussaf on shabbatot and yom tov) in the synagogue in the Repetition of the Amidah, during which the kohanim, members of the hereditary priesthood, lift their hands over the congregation and recite this text, word by word. It is not recited in the afternoon, because kohanim must be sober, and so it is not said during those times of day when the kohen might have drunk wine; for that same reason, it is recited at Minhah on fast days, and on Yom Kippur is even recited at Neilah.
In the Ashkenazi Diaspora it is done at mussaf of festival days.
The formulation of the mitzvah of Birkat Cohanim shows it is a mitzva De'oraita - a positive mitzvah from the Torah for the Cohanim to bless the Jewish People every day. This is how it is codified by the Sefer HaHinuch.
So how did the custom of not doing Birkat Cohanim daily start in the Diaspora?
Reasons given include:
The custom was to immerse in a mikveh before doing Birkat Cohanim. This was very hard to do in the Winter in Eastern Europe so they stopped doing it every day.
Rabbi Moshe Isserles wrote that "It has become the practice that the Cohanim do not raise their hands in blessing except on Yom Tov, as then they are in a state of happiness because of Yom Tov and a person who is in good spirits should administer the blessing. They are not in a state of happiness on other days even on Shabbatot as they are preoccupied with thoughts concerning their sustenance and over the cessation of their work. Even on Yom Tov they only do it at Musaf as then they are about to leave synagogue and rejoice in the celebration of Yom Tov."
Sephardi communities in diaspora also vary about when they do it - only days torah is read/ only shabbat/ every day/ only yom tov.....
The blessing traditionally recited by the priests before blessing the people is highly unusual.
Two questions emerge from this formula: First, why do the priests talk about being sanctified with the sanctity of Aaron instead of employing the usual formula, "who has sanctified us with God's commandments"? And second, why the mention of love at the end of the blessing?
The answer to our two questions is identical: Blessing depends on love. The Torah does not assign the priests the task of rote recitation. On the contrary, it calls upon them to love the people. Indeed, the Zohar declares that "a priest who does not love the people or is not loved by the people should not raise his hands to bless them" (Naso, 147b). Aaron, the first priest, is remembered as "a lover of peace and a pursuer of peace, one who love[d] people and brought them closer to Torah" (Mishnah, Avot 1:12). "The holiness of Aaron," says R. Shalom Noah Berezovsky (1911-2000), "flowed from his love." A priest devoid of love is a priest in name only.
Rabbi Reuven Bulka**:
When the kohanim bless the people, they must be compassionate. They cannot simply rush the blessing; it must be heartfelt and they need to hear it. The priestly blessing is a love blessing to all of the people, sanctified with the holiness of Aaron.
Ideas from "The Wonderfully Enigmatic Priestly Blessing"
From Birkat Kohanim, David Birnbaum and Martin S. Cohen, eds., New York: New Paradigm Matrix Publishing, 2016.
THE BLESSING OF THE CHILDREN AT THE SHABBAT TABLE
For the past several hundred years this blessing has been recited by parents at the beginning of Shabbat as a way of invoking God's blessing upon their children.
R. Naftali Zvi Yehudah Berlin (Netziv, 1816-1893) picks up on the fact that the blessing, recited over the whole people, is nevertheless stated in the second-person singular, and interprets that each person be granted blessings appropriate to them. "For the one engaged in Torah-blessings for their study; for the one engaged in trade- for success in business," and so on. We can take the Netziv's point one significant step further: Divine blessing is not generic but specific to each individual and her needs, dreams, and yearnings. God sees and cherishes us as individuals,and we pray for blessings accordingly.
The Netziv's explanation of "and protect you" goes further:. "May God protect you, lest the very blessing you receive turn into a stumbling block." The blessing of wealth, for example, can lead to greed, or stinginess, or lack of empathy. Or it can lead to a perpetual state of anxiety that one does not have enough or that one may lose what one has earned Crucially, the Netziv points out, even the blessing of Torah learning can yield rotten fruit: The Torah scholar can easily become arrogant or cause a desecration of God's name.
Every PARENT a blesser?!
In Reb Zalman's book "Davening", he describes in his chapter "Who am I to Bless?" how he once went for an audience with the late Lubavitche Rebbe. Reb Zalman tells how the Rebbe knew who he was and said to him "Zalman, you're a Priest, please keep me in mind when you recite the Priestly Blessing, during the high holy days".
By doing this the Rebbe was offering him a lesson, that when you offer a prayer to bring down a blessing it requires a postal address, don't do it just as a routine - keep specific people in mind. Bring down blessings for them.
He was, also, I think, showing Reb Zalman his own love by showing that he recognized him and also his important role as a Cohen.
THE HEART & THE HANDS

The Nitivat Shalom , N.S. asks on this Pasuk;
Q: Why does it mention that Ahron lifted his hands? The idea is that he blessed them. If the essence is the blessing why is it referred to as the lifting of the hands in general, until this day ?
Rabbi Yaakov Emden in his Siddur writes that it is a Minhag Yisroel to bless the children Friday night placing both hands on the child. In the Vilna Gaon's Siddur it also mentions the Minhag of giving a Bracha, however there it says you should only place the right hand on the child.
The pasuk we say when blessing the children on Shabbos Night is connected to Yackov blessing his grandchildren. We also say the Birkat Cohanim from parsha Nasso as part of the blessing.
Why end with SHALOM?
N.S. : The text of the Bracha for the Birkat Kohanim mentions blessing with Love specifically, this is not found in the text of any other bracha, it also singles out the holiness of Ahron .
Both of these are connected to blessing the people in general. If the Cohen does not have love for the people and the people don't have love for him then the blessing is not as affective. This is why love and through the holiness of Ahron are mentioned. They are guidelines to achieving and receiving Bracha.

CAN WE LOOK?
זוהר פרשת נזיר דף קמז
תאנא אמר רבי יוסי בשעתא דכהנא פריס ידוי אסיר ליה לעמא לאסתכלא ביה משום דשכניתא שריא בידוי.
After demonstrating that the Rambam and the Kabbalah are in fact in agreement, as exemplified by the case of divine providence, the author goes on to defend the Rambam’s explanation of various commandments, which were accused by latter scholars as being superficial. Yet, here as well, R. Gershon Henokh finds great mystical depth in the Rambam’s writings, for, as he stated earlier, in true Kabbalah, the literal and mystical meaning are always united.