Galatians 5:9
Memory Verse
A little leaven leavens the whole lump (Galatians 5:9).
Leaven in Scripture is typically used in a negative manner because of its characteristic to inflate dough. In Matthew 16:6, Jesus warns His disciples concerning the leaven of the Pharisees and Sadducees. After some deliberation, the disciples realized Jesus was speaking of their doctrine (Matthew 16:11–12).
Similarly, leaven within an assembly refers to a person who is blatantly involved in sin. In the case of Corinth, because the assembly permitted, and even boasted about allowing, a man who was committing an act not even the Gentiles would do, Paul rebukes them. Instead of boasting, they are to mourn so that this man is removed from them. As Paul says, a little leaven leavens the whole lump (1 Corinthians 5:6). Paul then compares leaven and unleavened to our fellowship among the saints. When doing wrong and malignant evil are permitted in the fellowship, they have a negative impact on all the saints (1 Corinthians 5:8). In contrast, unleavened fellowship involves pure intentions and truth, not taking the opportunity for wrong or malignant evil among the saints.
Therefore, when considering our fellowship with other saints, fornication and uncleanliness, or even covetousness, are not even to be named among us (Ephesians 5:3). We are to put to death these types of conduct in our bodies (Colossians 3:5–8). Furthermore, we are not to keep company with fornicators, those who are covetous, which is idolatry, railers, drunkards, or extortioners (1 Corinthians 5:11). Let us not be deceived: bad company corrupts useful habits (1 Corinthians 15:33).