Why does it say "Gan Na'ul"?
Rashi: This refers to the modesty of Bnos Yisrael; they refrain from Arayos.
Seforno: Har ha'Bayis, the place of the Mikdash, was not known in the days of David. This shows that salvation does not depend on the Mikdash!
Malbim (Melitzah): The Nefesh is a virgin. She was not defiled via the foreign gods, i.e. the power of the Yetzer, which arouses and desires. Nefashos stray after them and profane their Kedushah. No stranger entered this locked garden
What is "Gal Na'ul"?
Rashi #1: Gal is like a spring, like "Gulos Aliyos" (Yehoshua 15:19).
Rashi #2: Gal is a gate, like Teruku Gali (Brachos 28a - close the gates).
Malbim (Melitzah): It is what is close to the locked spring. These strangers did not approach her in thought or deed. Her source is sealed with the seal of Elokus and Kedushah, like when she was in her Kadosh place.
What do we learn from "Mayan Chasum"?
Torah Temimah citing Yuma 75a #1: Yisrael did not wantonly transgress Arayos. ("Zacharnu Es ha'Dagah" (Bamidbar 11:5) simply refers to fish; they did not complain about the Isur of Arayos.)
Torah Temimah citing Yuma 75a #2: Yisrael did not wantonly transgress Arayos already forbidden [to Bnei Noach. "Zacharnu Es ha'Dagah" was a complaint about the new Arayos forbidden to them.]
Seforno: It is the place of the Mizbe'ach. (It was not known in the days of David.)
