In ancient times, salt was used for medicinal and preservation purposes when refrigeration was non-existent. In the Old Testament, salt was used in the meat offerings unto the Lord (Leveticus 2:13).
Salt that loses flavour becomes contaminated and is dangerous and poisonous for use that it has to be thrown out (Luke 14:34-35). Salt is also referenced to the judgement of God (Mark 9:49).
As a flavour enhancer, we are to warn men about God's wrath, command them to repent, and do good works unto men that will glorify God in heaven (Matthew 5:13-16, Mark 9:50).
Leaven, on the other hand, has been associated with negative connotations throughout the Bible with false doctrines, sin and evil influences (Matthew 16:6-12, 1 Corinthians 5:6, Galatians 5:7-9). Leaven was also forbidden in the Old Testament during the Passover and the Feast of Unleavened Bread (Exodus 12:15-17, Exodus 34:25).
Today, pulpits preach salt as "flavour to the world" to justify a man-centered gospel that uses worldly methods to reach the lost and compromise everyday living with the world, rather than be salt as flavour to God. Leaven is also misintepreted as "positive growth in church numbers" by misquoting Matthew 13:33 and Galatians 5:9, when in fact, God likened leaven to the invasion of falsehoods in the church such as in 1 Corinthians 5:6-8, Acts 20:29-31, 2 Timothy 4:3-4, 1 Timothy 6:3-5, 2 Peter 2:1-3, 2 Corinthians 11:13-15, Jude 1:4 and Revelation 3:14-22.
Bread is likened to the Word of God, to Christ (Matthew 4:4, John 1:1-14, John 6:51). When the Jews were only allowed to eat bread without leaven during the Passover and Feast of Unleavened Bread (so much so that if someone ate bread with leaven, he/she would be cut off from the people - Exodus 12:15-19 ), it is a picture of how God takes His Word seriously and that His Word is Truth, that it must remain undefiled and uncontaminated by the leaven of falsehoods, man-made traditions and malice (Proverbs 30:5-6, John 17:17, John 6:63, 2 Timothy 3:16-17).
