Wisdom replaces ignorance in our minds when we realize that happiness does not lie in the accumulation of more and more pleasant feelings, that gratifying craving does not bring us a feeling of wholeness or completion.  It simply leads to more craving and more aversion.  When we realize in our own experience that happiness comes not from reaching out but from letting go, not from seeking pleasurable experience but from opening up in the moment to what is true, this transformation of understanding then frees the energy of compassion within us.  Our minds are no longer bound up in pushing away pain or holding on to pleasure.  Compassion becomes  the natural response of an open heart.