The works of Ādi Śaṅkarācārya

Sanatsujātīyam

p. 299

p. 299

अङ्गुष्ठमात्रः पुरुषोऽन्तरात्मा

In plain words

The Puruṣa, no larger than a thumb — that is the Self within.

Close to the Sanskrit

Of the measure of a thumb is the Puruṣa, the inner Self.