Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 39


तयोरेवं प्रहरतो: समशिक्षाबलौजसो: ।निर्विशेषमभूद् युद्धमक्षीणजवयोर्नृप ॥ ३९ ॥


tayor evaṁ praharatoḥsama-śikṣā-balaujasoḥnirviśeṣam abhūd yuddhamakṣīṇa-javayor nṛpa


As they thus fought, this contest between opponents of equal training, strength and stamina reached no conclusion. And so they kept on fighting, O King, without any letup.


Some ācāryas include the following two verses in the text of this chapter, and Śrīla Prabhupāda has also translated them in Kṛṣṇa: “At the end of each day’s fighting, they lived at night as friends in Jarāsandha’s palace, and the next day they fought again. In this way they passed twenty-seven days in fighting. On the twenty-eighth day, Bhīmasena told Kṛṣṇa, ‘My dear Kṛṣṇa, must frankly admit that I cannot conquer Jarāsandha.’”