Now as Jannes and Jambres withstood Moses, so do these also resist the truth: men of corrupt minds, reprobate concerning the faith.
Now - Greek, 'But.' It is no wonder there should be now such opponents to the truth, for their prototypes existed of old (Alford).
Jannes and Jambres - Egyptian magicians who resisted Moses (Exodus 7:11; Exodus 7:22). In a point so immaterial, where Scripture had not recorded the names, Paul takes those which Jewish tradition, or more probably history, assigned. Eusebius ('Praeparatio Evangelica') quotes from Numenius, 'Jannes and Jambres were sacred scribes (a lower order of priests in Egypt) deemed inferior to none in magic' Tradition made them to perish in the Red Sea. Hiller, derives Jannes from the Abyssinian 'trickster,' and Jambres, a juggler. Aan was the second predecessor of Joseph's Pharaoh. Ra, in the ending of Jambres, means the sun. The names were known to the Greeks and Romans, independently of Paul's mention of them. They probably were in some old chronicle of Israel's history (Smith, 'Dictionary of the Bible;' Pliny, 'H.N.' 30: 1; Apuleius, 'Apology' 24).
Resist - `withstand,' as before. They tried to rival Moses' miracles. So the false teachers shall exhibit lying wonders in the last days (Matthew 24:24; 2 Thessalonians 2:9; Revelation 13:14-15: cf. Acts 8:9; Acts 13:6; Acts 19:13; Acts 19:19).
Reprobate (Romans 1:28) - 'not abiding the test:' rejected on being tested (Jeremiah 6:30).