Danaparamita, the "perfection of generosity" or sharing is perhaps the most accessible entry into prajñaparamita, the "perfection of wisdom" which is the insight into the not-self nature of all phenomena.
"When you practice generosity, Subhuti, you should not rely on any object to be the cause of your generosity. You should not rely upon words, for they are merely labels. If you practice generosity without relying on causes or labels, you cannot conceive of the happiness. Subhuti, do you think that the space in the east can be measured?"
"No, honored one."
"Can the space in the west, the north, or the south, or up above or down below be measured?"
"No, honored one."
"In the same way, Subhuti, if you do not rely on any concept when practicing generosity, the happiness that results is as immeasurable as space."
The Diamond Sutra is one of the most famous of the prajñaparamita texts, in the form of a discourse given by the Buddha in response to a question from Subhuti as to how a bodhisattva (literally an "awakening being") should live. I think it's telling that the first thing the Buddha speaks about is the practice of dana, sharing or generosity.
The Buddha begins here because while prajñaparamita can seem a dense and complicated philosophical understanding related to emptiness -- the not-self nature of all phenomena -- the practice of generosity is available to all of us, no matter how intelligent or literate. It is the most accessible way -- as a practice -- to transcend attachment and clinging to self. When we share with others -- whether our possessions, time, energy of presence -- we are giving of ourselves, moving beyond our self-centeredness.
The main point being made in this particular passage is that when we are truly generous and not acting out of any sense of obligation, we experience a profound and easeful happiness. It brings us joy and happiness to give. Elsewhere, the Buddha points out that when we experience joy in anticipating sharing with someone, then we experience the actual joy of sharing, and then we experience another joy when we remember having shared with someone.
But also, the Buddha is pointing out that the "perfection" of giving arises when we go beyond thinking of causes or labels. Generally, if we give something, we may identify ourselves as the "giver" and the person we "gave" to as the "receiver" as if this were some nature. But the labels "giver" and "receiver" erase the fact that when we give, we ourselves are receiving the joy of giving. And the "receiver" is giving us the opportunity to share and thus feel good. So in the intimate experience of sharing there is no essential difference between "giver" and "receiver." This is danaparamita. And it is through this practice that we can awaken to the perfection of wisdom!