From Nagarjuna's Treatise on the Great Perfection of Wisdom
Question: Dana refers to the relinquishing of valuable things. Why does it state [in the text] that one perfects the dharma of having nothing which is relinquished?
Response: Dana is of two types: The first is that which transcends the world. The second is that which does not transcend the world. We are now discussing dana which transcends the world and which is devoid of characteristics. Because it is devoid of characteristics there is nothing which is relinquished. Hence it speaks of perfecting the dharma of having nothing whatsoever which is relinquished.
Moreover, because valuable things cannot be gotten at it is referred to as having nothing which is relinquished. In both the future and the past these things are empty. When they are analyzed in the present there is not a single dharma which is fixed. For this reason it is said that there is nothing which is relinquished.
Additionally, when the practitioner relinquishes valuable things, he is apt to think to himself, "This act of giving is greatly meritorious" and then, relying on this, may bring forth such fetters as pridefulness and [self] love. For this reason, it states that there is nothing which is relinquished. Because there is nothing which is relinquished, there is no pridefulness. Because there is no pridefulness, other fetters such as craving, [self] love and so forth are not brought forth.
Additionally, there are two types of people who give: The first is the worldly person. The second is the person who has transcended the world. The worldly person is able to relinquish valuable things but is not able to relinquish his giving. The person who has transcended the world is able to relinquish valuable things and is also able to relinquish his giving. Why? Because neither valuable things nor the mind which gives can be gotten at. It is for this reason that it speaks of perfecting the dharma of having nothing which is relinquished. What's more, in the dana paramita, it explains that the three factors of valuables, giver and recipient cannot be gotten at.