was mixed in with the new to make the bread rise.5 Though leaven can be used biblically in a positive or neutral sense (Matt 13:33; par. Luke 13:21), it more commonly serves as a symbol of unholiness, sin, or evil (cf. Matt 16:6–8; 1 Cor 5:6; Gal 5:9).6 The OT background is God’s command related to the exodus and the Feast of Unleavened Bread, when leaven was to be removed from the home and the penalty of eating bread with leaven was to be cut off from the congregation of Israel (Exod 12:14–20).