The works of Ādi Śaṅkarācārya

Sanatsujātīyam

p. 247

p. 247

तपोमूलमिदं सर्वं यन्मां पृच्छसि क्षत्रिय ।

In plain words

All of this has austerity at its root, O Kṣatriya, which you are asking me about.

Close to the Sanskrit

All this is rooted in austerity, O Kṣatriya, which you ask me about.