Śrīmad-Bhāgavatam · Text 10.21.19
Who is speaking and story frame
गा गोपकैरनुवनं नयतोरुदार-
वेणुस्वनै: कलपदैस्तनुभृत्सु सख्य: ।
अस्पन्दनं गतिमतां पुलकस्तरुणां
निर्योगपाशकृतलक्षणयोर्विचित्रम् ॥ १९ ॥
gā gopakair anu-vanaṁ nayator udāra
veṇu-svanaiḥ kala-padais tanu-bhṛtsu sakhyaḥ
aspandanaṁ gati-matāṁ pulakas taruṇāṁ
niryoga-pāśa-kṛta-lakṣaṇayor vicitram
My dear friends, as Kṛṣṇa and Balarāma pass through the forest with Their cowherd friends, leading Their cows, They carry ropes to bind the cows’ rear legs at the time of milking. When Lord Kṛṣṇa plays on His flute, the sweet music causes the moving living entities to become stunned and the nonmoving trees to tremble with ecstasy. These things are certainly very wonderful.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.