As they cross the lake, the disciples realize they forgot to bring bread. Jesus tells them to be careful and be on guard against the yeast of the Pharisees and Sadducees.
The disciples discussed this among themselves and came to the conclusion that Jesus said this because they forgot the bread.
Jesus responds to them by saying they have little faith. He says don’t you remember how I fed 5,000 men with 5 loaves of bread and had leftovers? Don’t you remember how I fed 4,000 men with 7 loaves and had leftovers? Of course I am not talking about bread. Then He says again to be on guard against the yeast of the Pharisees. Then the disciples understood that He was not referring to the yeast used in bread, but to the teaching of the Pharisees and the Sadducees.
For you and I, we need to be on guard as well. False teaching is still very prevalent in our world today. It is important that you understand for yourself what scripture says. If we just assume that the teaching we are hearing is correct, we might be siding with a false narrative and not even know it. Study the Word, understand what it says, and know for yourself what is right and what is wrong. Be on guard in all circumstances.
A Journey With Jesus 