It's from Second Kings 2:23-25, which is part of the Torah and the official 66 books of the bible. Though some (most) translations say that the curse is in the name of the lord/god.

From there Elisha went up to Bethel. As he was walking along the road, some boys came out of the town and jeered at him. “Get out of here, baldy!” they said. “Get out of here, baldy!” He turned around, looked at them and called down a curse on them. Then two bears came out of the woods and mauled forty-two of the boys. And he went on to Mount Carmel and from there returned to Samaria.