Shiva Purana

siva.sh/siva-purana/saturda-samhita/5/53

योगेश्वरावताराणां योगमार्गप्रवर्द्धकाः ।। महाशैवाश्च चत्वारः शिष्याः प्रत्येकमव्यया ।। ५३।।

sanskrit

In each of the incarnations of Yogeśvara, there are four disciples who make the path of Yoga flourish and who are eternal as well as great devotees of Śiva.

english translation

yogezvarAvatArANAM yogamArgapravarddhakAH || mahAzaivAzca catvAraH ziSyAH pratyekamavyayA || 53||

hk transliteration by Sanscript