Rav Mordechai Greenberg in Shabbat Bi-Shabbato:
"Take care and guard your soul very much, lest you forget the things that you saw with your own eyes... the day you stood on Chorev before your G-d" [Devarim 4:9-10]. Rashi feels that this is referring to the study of Torah, but the Ramban writes, "this is not true at all... rather I want to warn you... not to forget the events of Mount Sinai."
The main element of Mount Sinai was the intimate encounter between Bnei Yisrael and the Holy One, Blessed be He. As is written by the sages, "'He will kiss me with kisses on the mouth' [Shir Hashirim 1:2] – this can be compared to a young child who comes home from school and finds his father eating cake. He asks for a piece and his father cuts him one. But he says, what I want is to have some of what is in your mouth." That is how the Holy One, Blessed be He, gives the Torah to Moshe: "I speak to him from one mouth to another" [Bamidbar 12:11]. This direct contact is what is called an "enlightened face," as opposed to a situation when the Divine face is hidden. That is why we say in our prayers, "Our Father, bless us all together with the light of Your face, since with the light of Your face You gave us, our G-d, a Torah of life."
Where do we encounter the light of G-d's face after the events of Sinai? In the Tabernacle. Here is what the Ramban writes in the Torah portion of Teruma: "When G-d spoke to the nation of Yisrael face to face... this is the main thing desired in the Tabernacle, which is the Ark... And the mystic side of the Tabernacle is that the glory that was revealed at Mount Sinai rests there in a hidden manner." The "Keruvim," the images of angels facing each other on the cover of the Ark, continue the intimate face to face contact of Mount Sinai.
And what happens when the Tabernacle has been dismantled? The Rambam writes, "When the Ark is being carried, it is not carried on an animal... but the mitzva is to carry it on the shoulders... And it is carried face to face." That is, even when the Ark is being carried the Levites continue with the principle of face to face contact from Sinai, which is a sign of affection.
How can we continue this "light of the face" today, when the Temple does not exist? This is done in the synagogues, as the sages explained that it is written, "'This is how you shall bless Bnei Yisrael' [Bamidbar 6:23] – face to face" [Sotta 38]. In this way the Kohanim extent the light of the face that G-d presented to Yisrael with the giving of the Torah. That is why they say, "Let G-d light up His face to you" [6:26]. The sages explain, "This refers to the light of the Torah." And therefore the Kohanim are commanded to "bless His nation Yisrael with love." They are obligated to make an effort to bless the nation out of love, as an expression of the light of the face of the Holy One, Blessed be He.
It is written in the Midrash, "'Behold he stands behind our wall' [Shir Hashirim 2:9] – This refers to Sinai." In addition, "'Behind our wall' – this refers to the synagogues. 'Supervising through the windows' – from between the shoulders of the Kohanim. 'Peering out from the cracks' – from between the fingers of the Kohanim." And here we have the link to Sinai, through the carrying of the Ark on the shoulders of the Levites. And today the Shechina peeks out from between the fingers of the Kohanim when they bless the Jews. Our sages have written, "How did Yisrael merit the blessings of the Kohanim? As is written, 'This is how you shall bless Bnei Yisrael' [Bamidbar 6:23], and 'This is what you should say to the House of Yaacov' [Shemot 19:3]." [Bereishit Rabba 45].
The fact that the blessings of the Kohanim precede the dedication of the Tabernacle teaches us that the revelation of the Shechina does not depend on the existence of the Temple. Rather, G-d says, "every place where I mention My name I will come to you and bless you" [Shemot 20:21].
