kṛtāgasas te ’viduṣaḥ prabhāvam
kṣantuṁ prabho ’thārhasi mūḍha-cetaso
maivaṁ punar bhūn matir īśa me ’satī
Although Lord Kṛṣṇa protected the residents of Vraja by lifting Govardhana Hill, He had not yet punished Indra himself, and Indra feared that at any moment Śrī Kṛṣṇa might call the son of Vivasvān, Yamarāja, who punishes impudent persons who defy the laws of God.
Indra was quite fearful and thus begged the Lord’s forgiveness on the plea that he could be purified only by Kṛṣṇa’s mercy — that he was too stubborn to learn a good lesson through mere punishment.
In fact, despite Indra’s humility in this case, his heart was not completely purified. Later on in this canto we find that when Lord Kṛṣṇa once took a pārijāta flower from Indra’s kingdom, poor Indra again reacted violently against the Supreme Personality of Godhead. Thus, we should aspire to go back to our eternal home in the kingdom of Kṛṣṇa, and should not become entangled in the imperfect life of the material gods.