Mbh 2.30.6a

“Sahadeva, addressing Agni again, said,--‘O carrier of the sacrificial libations, it behoveth thee not to obstruct a sacrifice!’ Having said this, that tiger among men--the son of Madri--spreading some kusa grass on earth sat down in expectation of the (approaching) fire and in front of those terrified and anxious troops of his. And Agni, too, like the ocean that never transgresseth its continents, did not pass over his head. On the other hand approaching Sahadeva quietly and addressing that prince of the Kuru race, Agni that god of men gave him every assurance and said,--‘O thou of the Kuru race, rise up from this posture. O rise up, I was only trying thee. I know all thy purpose, as also those of the son of Dharma (Yudhisthira). But, O best of the Bharata race, as long as there is a descendant of king Nila’s line, so long should this town be protected by me. I will, however O son of Pandu, gratify the desires of thy heart. And at these words of Agni, O bull of the Bharata race, the son of Madri rose up with a cheerful heart, and joining his hands and bending his head worshipped that god of fire, sanctifier of all beings. And at last, after Agni had disappeared, king Nila came there, and at the command of that deity, worshipped with due rites Sahadeva, that tiger among men--that master of battle. And Sahadeva accepted that worship and made him pay tribute. And having brought king Nila under his sway thus, the victorious son of Madri then went further towards the south. The long-armed hero then brought the king of Tripura of immeasurable energy under his sway. And next turning his forces against the Paurava kingdom, he vanquished and reduced to subjection the monarch thereof. And the prince, after this, with great efforts brought Akriti, the king of Saurashtra and preceptor of the Kausikas under his sway.