佛祖統紀 29.36

29.36

持密語以希顯驗者。非與夫解第一義者妙心一悟當座而決。是以潔齊三業精明軌儀。誦專數言課充億萬。積月累歲而用成無間。重精疊思而始獲一感。維茲瑜伽五部之教。一切行果。廣大悉備。而於護國救世尤為至要。斯蓋佛道顯仁藏用。所以禦外務而回不信也撰瑜伽密教志（梵語瑜伽此云相應謂一切乘境行果所有諸法皆相應也）。

Those who uphold esoteric mantras in hopes of manifest efficacy are not like those who understand the ultimate truth, whose wondrous minds attain a single awakening resolved directly upon the seat. Therefore, they purify their three modes of karma and clarify the procedural guidelines; they recite dedicatedly a few words, their quota filling hundreds of millions; accumulating months and piling up years, their application becomes uninterrupted; redoubling refinement and layering contemplation, they only then obtain a single spiritual response. Now, as for these teachings of the five divisions of Yoga, all practices and fruits are vast and completely provided for; and for protecting the country and saving the world, they are exceptionally essential. This is indeed the Buddhist path manifesting benevolence while concealing its function, by which external affairs are managed and the unfaithful are converted. I have composed the 'Treatise on the Esoteric School of Yoga' (the Sanskrit word 'yoga' here means 'correspondence', meaning that all dharmas of the objects, practices, and fruits of all vehicles are mutually corresponding).