摩訶止觀 5.217

5.217

但此名通用，不獨在小乘，大乘亦名三假。附無明起，如幻如化，但有名字，實不可得。鏡中能成之四微尚不可得，況所成之幻柱？柱尚不可得，況歷時節「相續」，以幻化長短「相待」，寧復可得？舉易況難而明十喻。「即色是空，非色滅空。」即此義也。是名大乘隨理三假。

However, these terms are universally applicable, not restricted to the Hīnayāna; the Mahāyāna also refers to the three provisionalities. Arising in dependence on avidyā, like an illusion or an apparition, they exist only in name and are truly ungraspable. The four subtle atoms in a mirror that are capable of composing [an image] are themselves ungraspable; how much less the illusory pillar that is composed? If the pillar itself is ungraspable, how could the "continuity" across temporal shifts, or the "relativity" of illusory long and short, be graspable? Bringing forward the easy to illustrate the difficult clarifies the ten similes. "Form itself is emptiness, not that the destruction of form is emptiness." This is precisely the meaning. These are called the three provisionalities according to principle in the Mahāyāna.