“Lord Balarama is called “Douji” (the elder brother who protects and cares for the younger brother). After lifting Govardhana Hill Lord Krsna killed a succession of ferocious demons including Sankasura and Aristasura. Balarama hadn’t killed a demon for a long time, and He was concerned about Hi duty of protecting Krsna as His elder brother. Desiring to dress like Krsna, Lord Balarama once asked Krsna if He could wear His peacock feather and play Krsna’s flute for just one day. Krsna, who dearly loved His elder brother, agreed and personally gave His peacock feather and flute to Balarama.
“ Krsna and Balarama warmly embraced and then Balarama laughing happily, ran away playing gaily on Krsna’s flute. Mean-while, in Mathura, the wicked King Kamsa was about to send the horse demon, Keshi, to Vrindavana in order to kill Krsna. The Keshi demon asked King Kamsa, “How will I recognise Krsna?” Kamsa told him that it would be easy to tell, because Krsna would be the only person wearing a peacock feather and playing a flute.
“While Balaramji was fully enjoying His pastime of being Krsna for the day, the fierce horse demon, Keshi, stormed into Vrindavana. Seeing Balarama wearing a peacock feather in His crown and playing a flute, matching the description King Kamsa had given of Krsna, the Keshi demon roared up and gave Balarama a mighty kick that could have killed a full-grown elephant. This kick totally knocked the wind out of Balarama, and sent Him tumbling far away out of the demon’s sight. Thinking that he had killed Krsna, the Keshi demon galloped away. Balaramji, picking Himself up, began to cry. Balarama’s chest still hurting from the demon’s kick and He was short of breath. Balarama was hungry, very tired and sore all over from tumbling so far.
“Reaching home, Balarama immediately went to Krsna and returned His flute and peacock feather. Balarama told Krsna that He never again wanted to wear them, and that a huge horse demon had just violently kicked Him; thinking He was Krsna. Then Balaramji met His mother Rohini and fell asleep in her arms.
“Krsna replaced the peacock feather in His crown, tucked the flute back in His belt and walked into the village. Then Sri Krsna met the horrible horse demon and effortlessly killed him”
“Srila Prabhupada writes, ‘Lord Balarama is the original Vishnu; therefore anyone remembering these pastimes of Lord Balarama in the morning and evening will certainly become a great devotee of the Supreme Personality of Godhead and thus his life will become successful in all respects’ “(SB 1O.79.34p.)