From Nagarjuna's Treatise on the Great Perfection of Wisdom
(Dharmamitra Translation)

Additionally, giving is of two types. There is that which is pure and that which is not pure. As for impure giving, it may involve a kind of superficial giving in which one takes no interest. Or perhaps it may be done for the sake of obtaining wealth. Perhaps one gives because of shame or perhaps one gives as a means of reproval or perhaps one gives out of terror or perhaps one gives out of a desire to draw favorable attention or perhaps one gives out of a fear of death, or perhaps one gives with the intention of manipulating someone into feeling pleased, or perhaps one gives out of a feeling of obligation because one is rich and noble, or perhaps one gives as a means of struggling for dominance, or perhaps one gives out of jealousy or hatred, or perhaps one gives out of arrogance or a desire to elevate oneself above others, or perhaps one gives for the sake of fame or reputation, or perhaps one gives out of an attempt to lend efficacy to incantations and prayers, or perhaps one gives in an attempt to do away with misfortune and gain good fortune, or perhaps one gives in order to gain a following, or perhaps one gives in a disrespectful fashion in order to slight someone and make them feel lowly. All of the various sorts of giving such as these are classified as impure giving.

As for pure giving, any giving which stands in opposition to the above examples constitutes pure giving. Then again, giving for the sake of the Way is pure giving. When a pure mind arises which is devoid of any of the fetters and when one is not seeking for any reward in this or future lives, and when one does so out of reverence or sympathy, this qualifies as pure giving. Pure giving creates the provisions for moving on along the path to nirvana. Hence the reference to "giving for the sake of the Way."

If one performs acts of giving at a time prior to the time when one might realize nirvana, it creates a cause for blissful retribution among gods and men. Pure giving is like a floral wreath when first made and not yet withered which is fragrant, pure, fresh and radiant. When one performs acts of pure giving for the sake of nirvana, one's [also] being able to experience the fragrance of karmic rewards occurs in this way.

As the Buddha said, "There are two types of people who are rarely encountered in the world: The first, among those who have left the homelife, is a bhikshu who eats at the improper time and yet succeeds in gaining liberation. The second, among the white-robed householders, is one who is able to perform an act of pure giving." In life after life, the mark of this pure giving is never lost even after countless lifetimes. It is like a title deed which never loses its validity even to the very end.