大唐西域記 5.25-26

To the north of this stûpa are the ruins of a sanghârâma. here that Srilabdha (Shi-li-lo-to), a master of sastras belonging to the Sautrantika school, composed the Vibhasha Sastra of that school. To the south-west of the city 5 or 6 li, in an extensive grove of Amra trees, is an old sangharama; this is where Asanga Bodhisattva pursued his studies and directed the men of the age. Asanga Bodhisattva went up by night to the palace of Maitreya Bodhisattva, and there received the Yogacharya Sastra, the Mahayana Sutralankaratika, the Madhyanta Vibhanga Sastra, &c., and afterwards declared these to the great congregation, in their deep principles.

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."

After this Buddhasimha was the first to die. After three years, during which there was no message from him, Vasubandhu Bôdhisattva also died. Then six months having elapsed, and there being no message either from him, all the unbelievers began to mock and ridicule, [saying] Vasubandhu and Buddhasimha had fallen into an evil [way] of birth, and so there was no spiritual manifestation. After this, Asaṅga Bôdhisattva, during the first division of a certain night, was explaining to his [disciples] the law of entailing (or conferring on others) the power of samādhi, when suddenly the flame of the lamp was eclipsed, and there was a great light in space; [a Ṛishi descend]ing through the sky, and forthwith ascending the stairs of the hall, saluted Asaṅga. Asaṅga, addressing him, said, "[What has been the delay in] your coming? What is your present name?" In reply he said, "[At the] time of my death [I ascended to the Tuṣita] heaven, to the inner [assembly, in the immediate presence] of Maitreya, and was [born] in a lotus flower. On addressed me, saying, 'Welcome! thou vastly learned one! welcome! thou vastly learned one!' I then paid him my respects by moving round his person, and then directly came here to communicate my mode of life." Asanga said, "And where is Buddhasimha?" He answered, "As I was going round Maitreya I saw Buddhasimha among the outside crowd, immersed in pleasure and merriment. He exchanged no look with me;

how then can you expect him to come to you to communicate his condition?" Asanga answered, "That is settled; but with respect to Maitreya, what is his appearance and what the law he declares?" He said, "No words can describe the marks and signs (the personal beauty) of Maitreya. With respect to the excellent law which he declares, the principles of it are not different from those (of our belief). The exquisite voice of the Bodhisattva is soft and pure and refined; those who hear it can never tire; those who listen are never satiated." To the north-west of the ruins of the preaching-hall of Asanga about 40 li, we come to an old sangharama, bordering the Ganges on the north. In it is a stupa of brick, about 100 feet high; this is the place where Vasubandhu first conceived a desire to cultivate the teaching of the Great Vehicle. He had come to this place from North India. At this time Asanga Bodhisattva commanded his followers to go forward to meet him. Having come to the place, they met and had an interview. The disciple of Asanga was reposing outside the open window (of Vasubandhu), when in the after part of the night he began to recite the Dasabhumi Sutra.