A.T. Robertson Commentary Mark 8:15

"And he charged them, saying, Take heed, beware of the leaven of the Pharisees and the leaven of Herod." — Mark 8:15 (ASV)

Take heed, beware of the leaven of the Pharisees, and the leaven of Herod (Hορατε, βλεπετε απο της ζυμης των Φαρισαιων κα της ζυμης Hηρωιδου). Present imperatives. Note απο and the ablative case. Ζυμη is from ζυμοω and occurs already in Mt 13:33 in a good sense. For the bad sense see 1 Corinthians 5:6. He repeatedly charged (διεστελλετο, imperfect indicative), showing that the warning was needed. The disciples came out of a Pharisaic atmosphere and they had just met it again at Dalmanutha. It was insidious. Note the combination of Herod here with the Pharisees. This is after the agitation of Herod because of the death of the Baptist and the ministry of Jesus (Matthew 14:1–12; Luke 9:7–9). Jesus definitely warns the disciples against "the leaven of Herod" (bad politics) and the leaven of the Pharisees and Sadducees (bad theology and also bad politics).