Bhagavad Gita 11.54
भक्त्या त्वनन्यया शक्य अहमेवंविधोऽर्जुन। ज्ञातुं द्रष्टुं च तत्त्वेन प्रवेष्टुं च परन्तप।।11.54।।
bhaktyā tvananyayā śakya ahamevaṃvidho'rjuna| jñātuṃ draṣṭuṃ ca tattvena praveṣṭuṃ ca parantapa||11.54||
bhaktya tvananyaya shakya ahamevamvidho'rjuna jnatum drashtum ca tattvena praveshtum ca parantapa11.54
Meaning
But by single-minded devotion alone can I be known and seen in this form and in truth, and also be entered into, O Arjuna. Exclusive devotion is the only means.
परन्तु हे परन्तप अर्जुन! अनन्य भक्ति के द्वारा ही मैं तत्त्व से जाना, देखा और प्राप्त किया जा सकता हूँ।
This is verse 54 of 55 in Chapter 11 (Vishwaroopa Darshana Yoga) of the Bhagavad Gita.