Śrīmad-Bhāgavatam · Text 10.18.28
Who is speaking and story frame
अथागतस्मृतिरभयो रिपुं बलो
विहायसार्थमिव हरन्तमात्मन: ।
रुषाहनच्छिरसि दृढेन मुष्टिना
सुराधिपो गिरिमिव वज्ररंहसा ॥ २८ ॥
athāgata-smṛtir abhayo ripuṁ balo
vihāya sārtham iva harantam ātmanaḥ
ruṣāhanac chirasi dṛḍhena muṣṭinā
surādhipo girim iva vajra-raṁhasā
Remembering the actual situation, the fearless Balarāma understood that the demon was tṛying to kidnap Him and take Him away from His companions. The Lord then became furious and struck the demon’s head with His hard fist, just as Indra, the king of the demigods, strikes a mountain with his thunderbolt weapon.
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.