In Chapter Sixteen of Kṛṣṇa, the Supreme Personality of Godhead, Śrīla Prabhupāda points out that whereas previously Kāliya was vomiting poison, now his poison was exhausted and he began to vomit blood. Thus he had been cleansed of the vile contamination within his heart that had manifested as serpent’s venom. The word smṛtvā, “remembering,” is very significant here. The wives of Kāliya were actually serious devotees of Lord Kṛṣṇa, and according to the ācāryas they had often tried to convince their husband to surrender to Him. Finally, finding himself in unbearable agony, Kāliya remembered his wives’ advice and took shelter of the Lord. Śrīla Viśvanātha Cakravartī Ṭhākura explains that Kāliya’s archrival had traditionally been Garuḍa, the carrier of Viṣṇu. But now Kāliya realized that he was fighting an opponent who was thousands of times stronger than Garuḍa and who therefore could be only the Supreme Personality of Godhead. Thus Kāliya took shelter of Lord Kṛṣṇa.