Beyond this gross conception of form is another, subtle conception of form which is without formal shape and is unseen, unheard and unmanifest. The living being has his form beyond this subtlety, otherwise he could not have repeated births.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
अतः परं यदव्यक्तमव्यूढगुणव्यूहितम् । अदृष्टाश्रुतवस्तुत्वात्स जीवो यत्पुनर्भवः
ataḥ paraṃ yadavyaktamavyūḍhaguṇavyūhitam | adṛṣṭāśrutavastutvātsa jīvo yatpunarbhavaḥ
SB 1.3.32