佛祖統紀 1.69

1.69

序曰。如來聖人之利見於世也。則必有降本垂迹開迹顯本之妙存焉。夫本者。法身之謂也。迹者。八相之謂也（義見釋籤）由法身以垂八相。由八相以顯法身。本迹相融俱不思議。自非法華開近顯遠開迹顯本之談。則不足以深知此旨。故通列八相。別敘五時散引群經。會歸一實。用明一代化事始卒之義。則若本若迹。無餘蘊矣。

The preface states: When the sage Tathāgata favorably appeared in the world, there was necessarily the marvel of lowering the origin to project the traces, and opening the traces to reveal the origin. Now, the "origin" refers to the Dharmakāya. The "traces" refer to the eight aspects [of the Buddha's life] (the meaning is seen in the Shiqian). From the Dharmakāya the eight aspects are projected; through the eight aspects the Dharmakāya is revealed. Origin and traces interpenetrate, both being inconceivable. Were it not for the Lotus Sūtra's teaching of opening the near to reveal the distant and opening the traces to reveal the origin, it would be impossible to understand this principle deeply. Therefore, I comprehensively set forth the eight aspects and separately narrate the five periods, widely citing various sūtras to harmonize and return them to the One Reality, in order to clarify the significance of the beginning and end of the teaching events throughout his single lifetime. Thus, whether origin or trace, nothing remains obscured.