As fire, although situated in wood, is perceived to be different from the wood, as air, although situated within the mouth and nostrils, is perceived to be separate, and as the sky, although all-pervading, never mixes with anything, so the living entity, although now encaged within the material body, of which it is the source, is separate from it.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
यथानलो दारुषु भिन्न ईयते यथानिलो देहगतः पृथक् स्थितः । यथा नभः सर्वगतं न सज्जते तथा पुमान् सर्वगुणाश्रयः परः
yathānalo dāruṣu bhinna īyate yathānilo dehagataḥ pṛthak sthitaḥ | yathā nabhaḥ sarvagataṃ na sajjate tathā pumān sarvaguṇāśrayaḥ paraḥ
SB 7.2.43