妙法蓮華經玄義 4.96

4.96

云何如來室名梵行？無緣慈悲，能為法界依止，如磁石普吸，莫不歸趣。又以弘誓、神通、智慧引之，令得住是法中，故以如來室為梵行。

How does the Tathāgata's room designate pure practice? Unconditioned love and compassion can serve as the refuge for the dharma realm, like a lodestone attracting all things, such that none fail to return to it. Furthermore, guiding them with great vows, supernatural powers, and wisdom, causing them to dwell within this dharma, the Tathāgata's room is therefore taken as pure practice.