SB 10.78.38
rsaya ucuh
ilvalasya suto ghoro
balvalo nama danavah
sa dusayati nah satram
etya parvani parvani
Translation:
The sages said: A fearsome demon named Balvala, the son of Ilvala, comes here every new-moon day and contaminates our sacrifice.
Purport:
First the sages tell Lord Balarama the favor they would like Him to do for them.