Why does he tell her that she is beautiful?
Rashi: He praises [Yisrael] and desires them, and was pleased with their Korbanos.
Seforno: You are beautiful when you are My beloved - from the days of Yehoshua and the elders who lived long after him.
Malbim (Melitzah): The supreme Beloved praises all details of His Kalah now that He is isolated with her, and she uses her body for Avodas Hashem in the Mikdash.
How do her eyes resemble doves?
Refer to 1:15:2:1-5.
Rashi: Your color and appearance are like a dove, which clings to its mate. When they slaughter it, it does not quiver. Rather, it sticks out its neck. So you gave your shoulder to bear My yoke and fear.
Seforno: The judge and Kohen Gadol who instructs the generation, they cling to their Creator like a dove clings to her mate.
What is "mi'Ba'ad l'Tzamasech"?
Rashi #1: Refer to 4:1:4:2.
Rashi #2: Mi'Ba'ad is inside. In Tanach, Ba'ad is usually something that covers and protects, like "u'Ve'ad Kochavim Yachtom", "ha'Ve'ad Arafel" (Iyov 9:7, 22:13), "ha'Aretz Bericheha Va'adi" (Yonah 2:7). Mi'Ba'ad is something inside the protection. Tzamasech 1 is what is Metzamtzem (constricts) the hair, lest it go out, i.e. the hairnet and its ties.
Seforno: Tzamasech is an ornament of another woman's hair (wig).
Malbim (Melitzah): [Your eyes are like a dove's eyes, which look only at her mate,] even though they are tied and incarcerated in the body. Still, you gaze at Me.
Rashi: You cannot explain it is from the root Tzomes (junction), that the Sov is from the root. If so, it would have a Dagesh (a dot inside - it would be a Tov) when it is next to a Hei [or Vov] for a feminine [or masculine] pronoun, like Shabbos - "Chagah Chadashah v'Shabatah" (Hoshe'a 2:13), "Olas Shabbos b'Shabato" (Bamidbar 28:10). Rather, the Sov is in place of a Hei, and when it is next to a Vov or Hei, it is changed to a Sov, like Shifchah - Shifchaso, Shifchasah; Amah, Amaso, Amasah.
What do we learn from "Sa'arech k'Eder ha'Izim"?
Torah Temimah citing Brachos 24a: A woman's hair is considered Ervah.
Rashi: This is like the praise of a woman beloved to the Chasan. Inside your knots (tied over your hair), your hair is beautiful, and is bright and white like the hair of white goats that descend from the mountain. Their hair is bright from afar.
Seforno: Your natural hair, i.e. customs of your fathers, it is like hair of a flock of goats. Also it is guarded [from birth to be utterly clean] for Milas 1 (quality wool garments).
Malbim (Melitzah): Hair and teeth come from inside the body, and are expelled outside. In the metaphor, they represent revelation of inner light; it breaks out to the point that we sense it. This is why Ba'alei Kabalah attribute supreme Sefiros and clear lights to hair (countless sparks of Elokus) and teeth (32 paths of Chachmah 2 ). Intellect is exposed in two ways. (a) Countless ideas come from excesses of internal understanding, just like hairs sprout from excesses of the brain. Refer to 4:1:5:5. They hint also to understandings of Elokus. (b) Refer to 4:2:1:4.
Why does it say "she'Galshu me'Har Gil'ad"?
Rashi according to the metaphor: Yisrael is compared to this. Inside your camps and dwellings, even the empty ones among you are dear to Me like Yakov and his sons who descended from Har Gil'ad after Lavan caught up with them there.
Rashi citing Shir ha'Shirim Rabah: Like the soldiers who fought against Midyan in Ever ha'Yarden, in Eretz Gil'ad.
Rashi: Galshu is becoming bald. The Targum of Gibe'ach (Vayikra 13:41, bald) is Gelosh. When the animals descend from the mountain, the mountain is bald from them.
Seforno: All their hair is in back of the head. This is beautiful and dear.
Malbim (Melitzah): (a) Ideas are separate one from another, just like the goats from Har Gil'ad were "Akudim Nekudim u'Verudim" (Bereishis 31:10). Supreme worlds are called ha'Akudim veha'Nekudim. They are first revealed on high mountains. (b) This hints to "Rechev Elokim Ribosayim
