And Jesus said to them, “Watch out and beware of the leaven of the Pharisees and Sadducees.” … Then they understood that He did not say to beware of the leaven of bread, but of the teaching of the Pharisees and Sadducees. Matthew 16:6,12 (NASV)
Jesus warned his disciples to beware the teachings of the Pharisees and Sadducees. From elsewhere in the Gospels, it is clear that the Pharisees valued showy demonstrations of religious piety but lacked humility (Matthew 23:1-7), revered their own traditions over God’s commandments (Mark 7:6-13), and neglected internal righteousness to focus on external works. In essence, Jesus warned his followers to beware the dangers of legalism.
Of particular interest is the analogy of leaven, or yeast. When making bread, only a little yeast is used, but it is worked through the entire loaf so that all the dough rises. In the same way, a little “leaven” of legalism can work through our entire lives, causing us to lose focus on the cross and our righteousness which is by faith, and instead focuses us on our own efforts to win God’s approval. (This is not to say that works are bad or that obedience is wrong; on the contrary, we should delight is serving Christ. But our service should be born out of love for Him rather than an attempt to earn His love through our own efforts.)
Paul dealt with this same issue in the Galatian church. False teachers had begun to teach that adherence to Jewish law was required to be a Christian. Paul reminded them in Galatians 3:2-3: “This is the only thing I want to find out from you: did you receive the Spirit by the works of the Law, or by hearing with faith? Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh?” The church in Colossae also struggled with this issue, as Paul addressed in Colossians 2:8: “See to it that no one takes you captive through philosophy and empty deception, according to the tradition of men, according to the elementary principles of the world, rather than according to Christ.”
This applies not just to the churches of the first century but to modern Christians as well. There is a strong temptation to “begin” or “continue” Christ’s work in our lives by following our own laws and traditions rather than living by faith. But we can be reminded that the work of Jesus in our hearts comes by faith:
For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; not as a result of works, so that no one may boast. Ephesians 2:8-9 (NASV)
Although it is a temptation, we must resist the urge to rely on our own traditions and rules to achieve righteousness before God. We must accept, by faith, what He has offered, and realize that the righteousness He requires can only come by faith. And because a little leaven goes a long way, we must guard our hearts daily to walk and live by faith.