and Jambres. The two magicians of Pharaoh, who imitated some of the miracles of Moses. The Jannes and Jambres who “withstood Moses,” mentioned by St. Paul (2 Tim. iii. 8, 9), are supposed to be the same. The paraphrast Jonathan says they were the sons of Balaam.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894