佛祖歷代通載 7.114

7.114

初說教法。後皆著錄。綜覈深致無所漏失。故三藏十二部經。如九流之異。統其大歸終以三乘為本。後有羅漢菩薩。相繼著論。讚明經義以破外道。皆傍諸藏部大義。假立外問而以內法釋之。傳於中國。漸流廣矣。漢初沙門皆衣赤布。後乃易以雜色云。

What was initially preached as the Dharma was later committed to record, comprehensively examining its deep import without omitting anything. Thus, the three baskets (tripiṭaka) and twelve divisions of scripture, just like the distinctions among the nine philosophical schools, in their overarching purpose ultimately take the three vehicles (triyāna) as the fundamental basis. Later, arhats and bodhisattvas successively composed treatises to extol and elucidate the meaning of the sūtras in order to refute the non-Buddhists; all relied on the great import of the various baskets and divisions, positing external inquiries and explaining them through internal doctrine. When these were transmitted to China, they gradually spread far and wide. In the early Han, monks all wore red-cloth robes; later they changed to mixed colors.