Then Jesus gave them strict orders: “Watch out! Beware of the leaven of the Pharisees and the leaven of Herod.” – Mark 8:15 (CSB)
After Jesus again miraculously fed a large crowd, the Pharisees came to him and demanded a sign from him to prove his authenticity. Jesus refused and then went away with his disciples. While they sailed, Jesus warned them to “watch out for the leaven of the Pharisees and Herod.”
Matthew, in his gospel account, explains further what was meant: the “leaven” to which Jesus referred was the false teaching and beliefs the leaders of the region and religion promoted (Matthew 16:11-12). The Pharisees, especially, fit Paul’s description in Titus 1:16, “They claim to know God but they deny him by their works.” Often their demands upon people when far beyond God’s actual commands while they also neglected mercy and justice.
In every age of history, there have been people who have promoted lies and half-truths as being truths of God. The most dangerous of these are the teachings that bear much resemblance to what God has said. If we aren’t careful, such error can creep into our hearts and minds and then proceed to grow—just like dough that has been leavened with yeast.
Today, some false teachers say that we must do certain good works to be saved, instead of teaching that good works flow from a salvation that is by grace alone (Ephesians 2:8-10). Some teach that if you have enough faith then you’ll be prosperous and wealthy in this life, as they neglect the Bible’s descriptions of those who suffered much loss because of their faith (Hebrews 11:35-38). Some teach that the Bible’s sexual ethics are archaic and culture-determined, instead of teaching that Scripture gives us the truth of the unchanging God (2 Timothy 3:16-17).
How do we know the difference between what is true and what is false? We become intimately familiar with the Bible.
John told us to “test the spirits to see if they are from God, because many false prophets have gone out into the world.” Such tests include what one says about Jesus (1 John 4:1-3). Luke also praised the Bereans and presented them as an example for us because “they examined the Scriptures daily” to see if even the things Paul taught were true (Acts 17:11).
The more familiar we become with God’s word, the more equipped we will be to sort out the good from the bad. Examine Scripture, test what you hear or read, even what you read here, and make sure what is taught corresponds with the truth that God has revealed.