Easton's Bible Dictionary
The use of leaven was strictly forbidden in all offerings made to the Lord by fire (Leviticus 2:11 ; 7:12 ; 8:2 ; Numbers 6:15 ). Its secretly penetrating and diffusive power is referred to in 1 Corinthians 5:6 . In this respect it is used to illustrate the growth of the kingdom of heaven both in the individual heart and in the world (Matthew 13:33 ). It is a figure also of corruptness and of perverseness of heart and life (Matthew 16:6,11 ; Mark 8:15 ; 1 Corinthians 5:7,8 ).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain.
Easton, Matthew George. Entry for 'Leaven'. Easton's Bible Dictionary. http://www.studylight.org/dictionaries/ebd/l/leaven.html. 1897.