Shiva Purana
निराकारश्रयत्वेन साकाराश्रयतस्तथा ॥ तस्मात्सविषयं ध्यानमादौ कृत्वा सबीजकम् ॥ ९ ॥
Because it depends on formlessness it also depends on form Therefore, meditate on the subject in the beginning and seed it.
english translation
nirAkArazrayatvena sAkArAzrayatastathA ॥ tasmAtsaviSayaM dhyAnamAdau kRtvA sabIjakam ॥ 9 ॥
hk transliteration by Sanscript