Bhagavad Gita 6.33
अर्जुन उवाच। योऽयं योगस्त्वया प्रोक्तः साम्येन मधुसूदन। एतस्याहं न पश्यामि चञ्चलत्वात्स्थितिं स्थिराम्।।6.33।।
arjuna uvāca| yo'yaṃ yogastvayā proktaḥ sāmyena madhusūdana| etasyāhaṃ na paśyāmi cañcalatvātsthitiṃ sthirām||6.33||
arjuna uvaca yo'yam yogastvaya proktah samyena madhusudana etasyaham na pashyami cancalatvatsthitim sthiram6.33
Meaning
Arjuna confesses his doubt: Due to the restlessness of the mind, he does not see how this yoga of equanimity can be steadily maintained.
अर्जुन बोले — हे मधुसूदन! आपने जो यह समत्वयोग बताया है, मन की चंचलता के कारण मैं इसकी स्थिर अवस्था को नहीं देख पाता।
This is verse 33 of 47 in Chapter 6 (Dhyana Yoga) of the Bhagavad Gita.