Some of the teachings of the Lord Jesus are in the form of a straightforward sentence and some are figurative. The use of the word "leaven" in the few sentences that the Lord Jesus says about vigilance is in the figurative sense. That is why it is necessary to find the word meaning according to the principles of exegesis.The exegetical method used involves establishing the text of the text to be extrapolated, ie Matthew 16: 6, analysis of sentence structure and composing of translations, analysis of the context of the use of yeast at the time, excavation of theological points based on the meaning of words and wording in sentences, and the application of exegesis to the contemporary context.The conclusion of this study is, Jesus uses the term yeast because yeast is something commonly used in society, so its symbolic meaning is easily drawn according to what is understood by society. Yeast depicts the doctrine, and there is a common characteristic of yeast and the characteristics of doctrine; the decay caused by a small amount of yeast does not appear to be the process but the real change, as well as quite a bit of unhealthy teaching that is allowed to contaminate, has the potential to ruin the entire character of a person. The doctrine to watch out for is the preoccupation with the more outward than the spiritual, including arrogance, hypocrisy, and worldly worldview.