The Sufis insist on love because they have noticed that whatever is doing the seeking is also doing the loving, that the longing the seeker mistakes for hunger is, on closer inspection, the source recognizing itself through the seeker’s chest. Rumi’s reed cries because it remembers the reed-bed. The cry is not separation. It is the reed-bed singing through the cut reed.
This is not the love of the greeting card. It is closer to what John the Evangelist points at: God is love, and the one who dwells in love dwells in God. Not as a moral injunction. As a description of the substance. To love rightly is to recognize what is already there, behind the apparent separation, between any two things that look like two.
Every tradition has a vocabulary for this. The Christians call it agape. The Sufis call it ishq. The Hindus give it a hundred names, bhakti, prema, the love of Krishna for Radha and Radha for Krishna. The Buddhists, characteristically apophatic, call it karuna, the compassion that arises spontaneously when the illusion of separation thins.
If the ground is what we are and the return is what we do, love is the climate in which the doing happens. It is what becomes obvious on the other side of the veil. It is the form the source takes inside a being that has remembered.