The Question of Maitreya
The sutra known as The Question of Maitreya (Skt. Maitreyaparipṛcchā, Tib. བྱམས་པས་ཞུས་པ།, Wyl. ’phags pa byams pas zhus pa zhes bya ba theg pa chen po’i mdo) is found in the Ratnakuta (Heap of Jewels) section of the Tibetan Kangyur (Toh 85).
In this sutra, the Buddha explains to Maitreya the qualities that a bodhisattva needs to attain enlightenment quickly. The Buddha then recounts to Ananda how, in a former life, Maitreya revered a previous Buddha and, wishing to become just like him, at once realized that all phenomena are unproduced. It includes the famous "Prayer to Maitreya".
