維摩義記 2.42

2.42

Question: If one is reborn above in Tuṣita and later is born in the human realm before beginning to become a Buddha, that is two lifetimes. Why say "one"? Explanation: This lifetime is spoken of indeterminately by the sages. Relying on Nāgārjuna's treatise, it explains: this Maitreya has three lifetimes; the present lifetime has already been received and, being foolish, is left aside and not discussed; the subsequent birth in the human realm is the Buddha-body itself and therefore is also not counted. For this reason it is called "one".