大唐西域記 5.2.3

5.2.3

North-west of the Amra grove about a hundred paces is a stupa containing relics of the hair and nails of Tathagata. By its side are some old foundation walls. This is where Vasubandhu Bodhisattva descended from the Tushita heaven and beheld Asanga Bodhisattva. Asanga Bodhisattva was a man of Gandhara. He was born in the middle of the thousand years following the departure of Buddha from the world; and possessed of deep spiritual insight, he soon acquired a knowledge of the doctrine (of Buddha). He became a professed disciple, and attached himself to the school of the Mahisasakas, but afterwards altered his views and embraced the teaching of the Great Vehicle. His brother, Vasubandhu Bodhisattva, belonged to the school of the Sarvastivadins, and had inherited a wide fame, with a strong intelligence and penetrating wisdom and remarkable acumen. The disciple was Buddhasimha, a man whose secret conduct was unfathomable, of high talent and wide renown. These two or three worthies had often talked together in this way: "We all are engaged in framing our conduct so as to enjoy the presence of Maitreya after death. Whoever of us first dies and obtains the condition (of life), let him come and communicate it to us, that we may know his arrival there."