योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-211, verse-11

ध्यानेन त्वमपीतांश्चेत्स्थिरतां सुस्थिरात्मना ।
नयस्याशु तदेवैते स्थिरतां यान्त्यविघ्नतः ॥ ११ ॥

dhyānena tvamapītāṃścetsthiratāṃ susthirātmanā ,
nayasyāśu tadevaite sthiratāṃ yāntyavighnataḥ 11

11. If you can in the calm quietness of your mind and soul, secure the reflection of any of these spirits in your silent and steadfast meditation; you can without fail, have the visitation of the same in the inmost recess of your soul.