說無垢稱經疏 2.64

2.64

贊曰：依定起神變以化眾生，名定神變。舊名「定自在」，但以入出諸定自在，無神變義。說法無礙，名法自在。

Commentary: Relying on concentration (samādhi) to arouse miraculous transformations to convert sentient beings is called 'Concentration Miraculous Transformation' (Samādhi-vikurvaṇa-rāja). The old translation named him 'Concentration Master' (Samādhi-vaśavartin), which merely referred to entering and emerging from concentrations with mastery, lacking the meaning of miraculous transformation. Preaching the Dharma without hindrance is called 'Dharma Mastery' (Dharma-vaśavartin).