Whoever has fallen far from their origin seeks once more the time of reunion.
هر کسی کو دور ماند از اصلِ خویش / باز جوید روزگارِ وصلِ خویش
Her kesî k'û dûr mând ez asl-ı hîş / Bâz cûyed rûzgâr-ı vasl-ı hîş
Rumi, Masnavi, Book I, couplet 4 (Ganjoor text).
The fourth couplet of the Masnavi is the key to the whole book.
The reed was cut from the reed bed; that is why it cries.
But the cry is not a loss; it is a remembering: whoever has fallen far from their origin has not forgotten it.
That unnamed longing within a person is a memory left from the Hidden Treasure.
To long is to know that you were once there.