Shiva Purana
ध्याता ध्यानं तथा ध्येयं यच्च ध्यानप्रयोजनम् ॥ एतच्चतुष्टयं ज्ञात्वा योगं युञ्जीत योगवित् ॥ ५७ ॥
The knower of Yoga shall practise Yoga with the knowledge of four things—the meditator, the meditation, the object of meditation and the benefit of meditation.
english translation
dhyAtA dhyAnaM tathA dhyeyaM yacca dhyAnaprayojanam ॥ etaccatuSTayaM jJAtvA yogaM yuJjIta yogavit ॥ 57 ॥
hk transliteration by Sanscript