華嚴經探玄記 19.41

19.41

Under the spiritual friend of the ninth practice of good dharmas: First, in adducing the Dharma to exhort cultivation, the city being named Sthirā ('Stable Abode') means that it tallies with the true Dharma and is not destroyed by conditions, hence it is named after this. The upāsikā being named Acalā ('Immovable') is because when she first generated the mind, she was not moved by the two vehicles or afflictions, hence she was named after this.