Song of Solomon 5:2
I sleep, but my heart waketh: it is the voice of my beloved that knocketh, saying, Open to me, my sister, my love, my dove, my undefiled: for my head is filled with dew, and my locks with the drops of the night. I sleep, but my heart waketh: it is the voice of my beloved that knocketh, saying, Open to me, my sister, my love, my dove, my undefiled: for my head is filled with dew, and my locks with the drops of the night.
The picture is of a beloved arriving in the night, knocking at the door and asking to be let in, his head wet with dew and his locks damp with the drops of the night. The knocking one is Jesus seeking entrance to the heart, calling for admission. The hearts where He waits are closed against Him by pride and unbelief. He knocks persistently, again and again with long patience, waiting outside through the night until His head is damp from the night air. Sinners must open their hearts to receive Him and must not put off seeking Him until it is too late.