"...the brahmanas of Naimisaranya advised Baladeva to atone for the death of Romaharsana. After killing a demon named Balvala, Baladeva traveled and bathed in holy places until He at last came to the Battlefield of Kuruksetra, where Bhima and Duryodhana were fighting. Then He returned to Dvaraka and went again to Naimisaranya, where He instructed the rsis. Then He left with His wife Revati.
Srimad-Bhagavatam, 10th Canto Summary
"The brahmanas could understand the purpose of the Lord, and thus, they suggested that He atone for His actions in a manner which would be beneficial to them. They said, "Our dear Lord, there is a demon of the name Balvala. He is the son of Ilvala, but he is a very powerful demon, and he visits this sacred place of sacrifice every fortnight on the full moon and moonless days and creates a great disturbance to the discharge of our duties in the sacrifice. O descendant of the Dasarha family, we all request You to kill this demon. We think that if You kindly kill him, that will be Your atonement on our behalf. The demon occasionally comes here and profusely throws upon us contaminated, impure things like pus, blood, stool, urine and wine, and he pollutes this sacred place by showering such filth upon us. After killing Balvala, You may continue touring all the sacred places of pilgrimage for twelve months, and in that way You will be completely freed from all contamination. That is our prescription."
Krsna Book, Chapter 78
"Lord Balarama prepared Himself to meet the demon Balvala. At the time when the demon usually attacked the sacred place, there appeared a great hailstorm, the whole sky became covered with dust, and the atmosphere became surcharged with a filthy smell. Just after this, the mischievous demon Balvala began to shower torrents of stool and urine and other impure substances on the arena of sacrifice. After this onslaught, the demon himself appeared with a great trident in his hand. He was a gigantic person, and his black body was like a huge mass of carbon. His hair, his beard and his mustache appeared reddish, like copper, and because of his great beard and mustache, his mouth appeared to be very dangerous and fierce. As soon as He saw the demon, Lord Balarama prepared to attack him. He first began to consider how He could smash the great demon to pieces. Lord Balarama called for His plow and club, and they immediately appeared before Him. The demon Balvala was flying in the sky, and at the first opportunity Lord Balarama dragged him down with His plow and angrily smashed the demon's head with His club. By Balarama's striking, the forehead of the demon became fractured. There was a profuse flow of blood from his forehead, and he began to scream loudly. In this way the demon, who had been such a great disturbance to the pious brahmanas, fell to the ground. His falling was like a great mountain with a red oxide peak being struck by a thunderbolt and smashed to the ground.
The inhabitants of Naimisaranya, learned sages and brahmanas, became most pleased by seeing this, and they offered their respectful prayers to Lord Balarama. They offered their heartfelt blessings upon the Lord, and all agreed that Lord Balarama's attempt to do anything would never be a failure. The sages and brahmanas then performed a ceremonial bathing of Lord Balarama, just as King Indra is bathed by the demigods when he is victorious over the demons. The brahmanas and sages honored Lord Balarama by presenting Him first-class new clothing and ornaments and the lotus flower garland of victory, the reservoir of all beauty, which was was never to be dried up, being in everlasting existence.
Krsna Book, Chapter 79
Bhaktivedanta Book Trust. Excerpted from text and purport of HDG A.C. Bhaktivedanta Swami Srila Prabhupada.