Shiva Purana
स्थावरत्वमनुप्राप्य भक्तानुग्रहकारणात् । ते दत्ता विष्णुभक्तेभ्यश्चतुर्वर्णेभ्य एव च ८ ।
They became immobile. In order to bless the devotees they were given to the four Varṇas devoted to the worship of Viṣṇu.
english translation
sthAvaratvamanuprApya bhaktAnugrahakAraNAt । te dattA viSNubhaktebhyazcaturvarNebhya eva ca 8 ।
hk transliteration by Sanscript