Tafsiran Kidung Agung 5:2: Rashi & Ezra ben Solomon

I slept. When I was confident and calm in the first Beis Hamikdosh, I despaired of worshiping the Holy One, Blessed Is He, as one who slumbers and falls fast asleep.

I was asleep: The shekhinah states, I was asleep in Babylonian exile.

But my heart was awake. This is the Holy One, Blessed Is He. This is expounded in the Pesikta.⁹Alternatively, ולבי ער, refers to the prophets and the sages who were constantly exhorting and rousing the Bnei Yisroel to rise from their spiritual sluggishness. (Sforno)

But my heart was awake. The Holy One, Blessed Is He, Who is, “the Rock of my heart and my portion,”¹⁰Tehillim 73:26. is awake to guard me and to benefit me.

A sound! My beloved knocks. He rests His Divine Presence upon the prophets and He warns through them by, “rising early and sending forth.”¹¹Yirmiyahum 7:25.

Open for me. Do not cause Me to depart from you.

For my head is drenched [as though] with dew. A term referring to a man who comes at night, knocking on the door of his beloved. He says thus, “Out of love for you, I have come at night at the time of dew or rain.” And the allegory is as follows: “For my head is drenched [as though] with dew,” because I am full of good will and satisfaction with Avrohom your forefather,¹²ראשי alludes to Avrohom who was first [=ראש] to believe in God. (Sifsei Chachomim) whose deeds were pleasing to Me as dew. And behold, I come to you, laden with blessings and the payment of reward for good deeds if you return to Me.