My dear King, by constantly meditating upon the Supreme Lord, Vāsudeva, and by applying clear and logical intelligence, you should carefully consider your true self and how it is situated within the material body.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
एवमात्मानमात्मस्थमात्मनैवामृश प्रभो । बुद्ध्यानुमानगर्भिण्या वासुदेवानुचिन्तया
evamātmānamātmasthamātmanaivāmṛśa prabho | buddhyānumānagarbhiṇyā vāsudevānucintayā
SB 12.5.9