Upaniṣads · Chāndogya 7.20

Chāndogya 7.20.1

यदा वै निस्तिष्ठत्यथ श्रद्दधाति नानिस्तिष्ठञ्छ्रद्दधाति निस्तिष्ठन्नेव श्रद्दधाति निष्ठा त्वेव विजिज्ञासितव्येति निष्ठां भगवो विजिज्ञास इति ॥ ७.२०.१ ॥

When one stands firm, then one has faith. One does not have faith without standing firm; only while standing firm does one have faith. But steadfastness itself must be inquired into. "Venerable sir, I wish to inquire into steadfastness."