佛祖統紀 4.12

4.12

I comment: According to the Xingfa jing, 'After three months I shall enter nirvāṇa'; thus we know that the preaching of the Xingfa jing occurred on the full moon of the eleventh month in the xin-wei year. According to the Sheng Daoli jing, he stayed for the three-month retreat; thus we know that when the preaching of the Xingfa jing was completed, he went to Trāyastriṃśa on that very day. According to this sutra, as the three months were drawing to a close he wished to enter nirvāṇa; thus we know that on the fourteenth day of the second month of this year he descended to Jambudvīpa, and on the fifteenth day he entered nirvāṇa.