From Nagarjuna's Treatise on the Great Perfection of Wisdom
Question: What is meant by fulfillment of dana paramita within the body produced from the karma of the fetters?
Response: This refers to when one has not yet gained the Dharma body and the fetters have not yet been brought to an end. One becomes able to give completely of all that one possesses, both internally and externally, including all manner of precious objects, one's head, eyes, marrow, brain, country, wealth, wives, and sons, and does so without one's mind moving or turning away. For instance, Prince Sudana (In the language of Ch'in, this means "fine fondness.") who made a gift of his two sons to a brahman. Next, he relinquished his wife and yet his mind [still] did not turn away from it.
In ways such as this, and in all sorts of physical bodies, one gives even one's own wives and sons and yet does not stint at all, treating it as if it were only setting aside grass or trees. One contemplates those things which are given and realizes that they exist on the basis of conditions. When one pursues this and seeks to find their reality, it can never be found. Everything is characterized by being pure and like nirvana. And so this proceeds until one realizes the patience resulting from seeing dharmas as unproduced. This is what is meant by fulfillment of dana paramita while abiding in a body produced from the karma of the fetters.