Shiva Purana
ध्यानार्थं चैव सर्वेषामरूपो रूपवानभूत् ॥ स एव च शिवस्साक्षाद्भक्तवात्सल्यकारकः ॥ ९ ॥
The formless one became one with forms in order to facilitate meditation. He alone is Śiva himself, favourably disposed towards his devotees.
english translation
dhyAnArthaM caiva sarveSAmarUpo rUpavAnabhUt ॥ sa eva ca zivassAkSAdbhaktavAtsalyakArakaH ॥ 9 ॥
hk transliteration by Sanscript