Matthew 13:33
Another parable He spoke to them: “The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened.â€
Leaven, as a fermenting substance, is figurative of sin, Apostle Paul said (1 Corinthians 5: 6-8) “Your boasting is not good. Don’t you know that a little yeast works through the whole batch of dough? Get rid of the old yeast that you may be a new batch without yeast– as you really are. For Christ, our Passover lamb, has been sacrificed. Therefore let us keep the Festival, not with the old yeast, the yeast of malice and wickedness, but with bread without yeast, the bread of sincerity and truth.” Similarly Apostle Paul warned the Galatians of the doctrine of the cult of the circumcision when he said, “A little yeast works through the whole batch of dough.” Galatians 5:9.
Leaven also represents all false doctrines, Jesus warned against the doctrines of the Pharisees and the Sadducees in Matthew 16: 6-12 “Be careful,” Jesus said to them. “Be on your guard against the yeast of the Pharisees and Sadducees.” They discussed this among themselves and said, “It is because we didn’t bring any bread.” Aware of their discussion, Jesus asked, “You of little faith, why are you talking among yourselves about having no bread? Do you still not understand? Don’t you remember the five loaves for the five thousand, and how many basketfuls you gathered? Or the seven loaves for the four thousand, and how many basketfuls you gathered? How is it you don’t understand that I was not talking to you about bread? But be on your guard against the yeast of the Pharisees and Sadducees.” Then they understood that he was not telling them to guard against the yeast used in bread, but against the teaching of the Pharisees and Sadducees. In summary, Yeast” or “Leaven” always has a negative connotation in the Bible.
We can learn from this parable most importantly, that the kingdom of heaven teachings together with the program of God in this age may be corrupted by false doctrines and unbiblical programs. False teachings and professed Christian lives always seek to hide behind God’s word. Apostle Paul gave instructions to Timothy:
1 Timothy 4:1-8  “The Spirit clearly says that in later times some will abandon the faith and follow deceiving spirits and things taught by demons. Such teachings come through hypocritical liars, whose consciences have been seared as with a hot iron. They forbid people to marry and order them to abstain from certain foods, which God created to be received with thanksgiving by those who believe and who know the truth. For everything God created is good, and nothing is to be rejected if it is received with thanksgiving, because it is consecrated by the word of God and prayer. If you point these things out to the brothers, you will be a good minister of Christ Jesus, brought up in the truths of the faith and of the good teaching that you have followed. Have nothing to do with godless myths and old wives’ tales; rather, train yourself to be godly. For physical training is of some value, but godliness has value for all things, holding promise for both the present life and the life to comeâ€
2 Timothy 3:5“Having a form of godliness but denying its power. Have nothing to do with themâ€
2 Timothy 4:3-5 “For the time will come when men will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great number of teachers to say what their itching ears want to hear. They will turn their ears away from the truth and turn aside to myths. But you, keep your head in all situations, endure hardship, do the work of an evangelist, discharge all the duties of your ministryâ€
Apostle Peter also said in his epistle ( 2 Peter 3:3-5) “First of all, you must understand that in the last days scoffers will come, scoffing and following their own evil desires. They will say, “Where is this ‘coming’ he promised? Ever since our fathers died, everything goes on as it has since the beginning of creation.” But they deliberately forget that long ago by God’s word the heavens existed and the earth was formed out of water and by waterâ€
We must be very watchful in these last days, so many false teachings and false brethren are circulating our community. They just want to enslave us, don’t give them a chance. (Galatians 2: 4) “This matter arose because some false brothers had infiltrated our ranks to spy on the freedom we have in Christ Jesus and to make us slavesâ€.
You must seek after the truth, it could be harsh initially, but the end is joy. Proverbs 14:34 “Righteousness exalts a nation, but sin is a disgrace to any peopleâ€
Prayer: Lord Jesus help me to be watchful of every false doctrine, give me strength to seek after the truth all the days of my life.