8:15 leaven of the Pharisees and . . . Herod. Jesus uses an everyday ingredient of bread as a metaphor (Luke 12:1 note). What seems like an innocent, indeed legitimate request for a sign (on Herod’s desire for miracles, see Luke 23:8) is actually a rejection of His ministry and all His previous signs. Jesus is warning His disciples against superficial conceptions of His role and preparing them for His teaching concerning the true meaning of His coming and of His cross (vv. 27, 31). Such teaching remained incomprehensible to many Jews (1 Cor. 1:22, 23).