Thereafter, you should meditate upon the limbs of Viṣṇu, one after another, without being deviated from the conception of the complete body. Thus the mind becomes free from all sense objects. There should be no other thing to be thought upon. Because the Supreme Personality of Godhead, Viṣṇu, is the Ultimate Truth, the mind becomes completely reconciled in Him only.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तत्रैकावयवं ध्यायेदव्युच्छिन्नेन चेतसा । मनो निर्विषयं युक्त्वा ततः किञ्चन न स्मरेत् । पदं तत्परमं विष्णोर्मनो यत्र प्रसीदति
tatraikāvayavaṃ dhyāyedavyucchinnena cetasā | mano nirviṣayaṃ yuktvā tataḥ kiñcana na smaret | padaṃ tatparamaṃ viṣṇormano yatra prasīdati
SB 2.1.19