Two Wings of a Bird

In Buddha Dharma it's often said that wisdom and compassion are like the two wings of a bird. Why are wisdom and compassion like the two wings of a bird? The universal instinct of beings in wanting happiness and not suffering is called great compassion. The universal intelligence of beings which can fulfill this compassion is called great wisdom. Therefore these two great universal virtues of wisdom and compassion are what fulfill the hearts and minds of sentient beings. Like the metaphor of the bird in flight, flying free and being one with its nature. So too, fulfilling the hearts and minds of sentient beings to be free in accordance with their true nature.