"In the eighth chapter of " Shri Krishna Samhita', eighteen evils have been cited from the 13th sloka to the end as obstacles to Vraja-bhajana. If breaking up of Yamalarjuna and the vanity of a Brahmin performing sacrifices are added, these will make up to 20 obstacles. These are all adverse tattvas to Vraja bhajana. The aspirant devoted to Nama bhajana, in the very beginning should loudly address All-Powerful Hari, praying always to drive out these evils. If he does, his heart will be purified. If the devotees cry out most humbly and piteously to Hari to drive out the trouble of those Asuras whom Krishna has destroyed from the domain of their heart, Hari Himself will remove those evils. But they will have to drive out themselves, with their own efforts the troubles of those Asuras whom Baladeva has killed. This is the mystery of Vraja-bhajana.
Dhenukasura is the evil of licentiousness, gain, honor and aspiration for selfish end. The aspirant will remove these evils with his own care and effort and obtaining mercy of Krishna. Loss of knowledge of swarupa of self, swarupa of Nama and relationship with swarupa of owns adorable Deity, ignorance and Avidya constitute Dhenukasura.
With the greatest care and endeavor the aspirant will have to remove this evil and restore his self-knowledge.
Lewdness for male or female, greed for wealth, effort for acquiring material prosperity, increasing one's honor, fame and reputation etc., are very pernicious evils and knowing these as strong impediments to Nama-bhajana, the aspirant, with his best acre and effort will remove them.
If humility becomes very deep and intense, Krishna will be merciful. In that case, feeling of Baladeva will arise in his mind and then these will be destroyed in no time. Then favorable and smooth cultivation of Bhajana will gradually improve. This process is naturally very secret and should be learnt from a good preceptor with clear mind.
The Dhenukasura pastime, Krishna Book Chapter 15 by A.C Bhaktivedanta Swami.
"Immediately upon entering the Talavana, Balarama began to yank the trees with His arms, exhibiting the strength of an elephant. Because of this jerking, all the ripe fruits fell down on the ground. Upon hearing the sound of the falling fruits, the demon Dhenukasura, who was living there in the form of an ass, approached with great force, shaking the whole field so that all the trees began to move as if there were an earthquake. The demon appeared first before Balarama and kicked His chest with his hind legs. At first, Balarama did not say anything, but the demon with great anger began to kick Him again more vehemently. This time Balarama immediately caught hold of the legs of the ass with one hand and, wheeling him around, threw him into the treetops. While he was being wheeled around by Balarama, the demon lost his life. Balarama threw the demon into the biggest palm tree about, and the demon's body was so heavy that the palm tree fell upon other trees, and several fell down. It appeared as if a great hurricane had passed through the forest, and all the trees were falling down, one after another. This exhibition of extraordinary strength is not astonishing because Balarama is the Personality of Godhead known as Ananta Sesa Naga, who is holding all the planets on the hoods of His millions of heads. The whole cosmic manifestation is maintained by Him exactly as two threads hold the weaving of a cloth.
After the demon was thrown into the trees, all the friends and associates of Dhenukasura immediately assembled and attacked Balarama and Krsna with great force. They were determined to retaliate and avenge the death of their friend. But Krsna and Balarama began to catch each of the asses by the hind legs and, exactly in the same way, wheeled them around. Thus They killed all of them by throwing them into the palm trees. Because of the dead bodies of the asses, there was a panoramic scene. It appeared as if clouds of various colors were assembled in the trees. Hearing of this great incident, the demigods from the higher planets began to shower flowers on Krsna and Balarama and beat their drums and offer devotional prayers.
A few days after the killing of Dhenukasura, people began to come into the Talavana forest to collect the fruits, and animals began to return without fear to feed on the nice grasses grown there. Just by chanting or hearing these transcendental activities and pastimes of the brothers Krsna and Balarama, one can amass pious activities."