Typical of this dream-like poem, the young woman suddenly finds her beloved without any explanation of how or where. This is how things would work in a dream-like poem. Not everything is explained or even makes sense. The point is that she has found the one whom her soul loves.
Having found him she holds him tightly so that she never loses him again.
The root of the Hebrew word rph translated as would not let him go
means to leave alone
or to forsake,
and it communicates her anxiety.1 The young man is not lost to her, but her longings for the man she loves bring with them anxieties because of the possible dangers to their relationship in this fragile and uncertain stage before marriage.
4 Scarcely had I passed them when I found him whom my soul loves. I held him, and would not let him go until I had brought him into my mother’s house, and into the chamber of her who conceived me.