Iannes and Mambres, or Jannes and Jambres, are names given to the magicians who contended with Moses and Aaron and were discomfited by the Hebrew leaders in the Hebrew Bible book of Exodus. These names were not given in the book of Exodus itself, but they appear in 2 Timothy III:8 in the New Testament.
They also appear in Pliny the Elder's Natural History, together with Moses, as famous magicians of antiquity; Pliny's citation is also referred to in Apuleius. Numerius, a Pythagoreanphilosopher, calls them sacred Egyptian scribes. Origen says that there was an apocryphal book called The Book of Jannes and Jambres, containing details of their exploits, and that St Paul's epistle was quoting from it. This book has not been rediscovered.
Jewish traditions in the Targums preserve other half-legendary lore about the pair. They are called the sons of Balaam, the unwitting prophet of Pelor. It was also claimed that they converted to Judaism, and that they left Egypt at the Exodus; however, they perished on the way, either at the Red Sea, or the destruction of the Golden Calf, or at the slaughter of Phinehas and his followers.
Pliny's coupling of Moses with Iannes as founders of a system of sorcery will not seem strange to one who reads the dialogue which the Rabbis put in the mouths of these persons.
Iannes and Iambres tell Moses that bringing sorcery into Egypt is - to substitute an English proverb for theirs - "bringing coals to Newcastle"; the Egyptians had too much of it to care for more.
The passage is evidence of a matter recorded in the tradition, and which is in itself highly probable, viz., that the Jews, when their relations with the Prophet became strained, endeavored to deal with him by sorcery.