Now they had forgotten to bring bread, and they had only one loaf with them in the boat. And he cautioned them, saying, “Watch out; beware of the leaven of the Pharisees and the leaven of Herod.” And they began discussing with one another the fact that they had no bread. And Jesus, aware of this, said to them, “Why are you discussing the fact that you have no bread? Do you not yet perceive or understand? Are your hearts hardened? Having eyes do you not see, and having ears do you not hear? And do you not remember? When I broke the five loaves for the five thousand, how many baskets full of broken pieces did you take up?” (Mark 8:14-19)
We are in an age of information. We are constantly bombarded with facts and statements, more than we can possibly take in. How we deal with it, whether we are aware of it or not, is to filter this information. We retain (hopefully!) the pieces of information that are relevant to us, whilst the information that has no bearing on our lives or of no interest is quickly forgotten. Men seem to be particularly adept at this kind of filtering, although the problem is that sometimes the filter switches on when it shouldn't (as my wife will testify! ;-))
As well as weeding out irrelevant facts, this inbuilt information-filter can also highlight stuff for us that is especially relevant. Our ears prick up (or burn! ;-)) when we hear our names mentioned. When we hear someone talking about something that we have been chewing over ourselves it grabs our attention. God himself sometimes interacts with us using this principle. Repetition is the prophetic equivalent of bold italics (Ge 41:32). God will often bring the same word to us through different people or in different ways in order to grab our attention. As well as establishing and confirming the word it is designed to help us receive it. Words of knowledge can also work along these lines, a seemingly meaningless piece of information to us, can have a dramatic impact on someone if we trust God enough to bring it. Why? Because to them it is not meaningless or trivial but laced with significance.
The problem is that our "information-filter" can sometimes get over-zealous and corrupt the original message! If someone mentions a subject or activity that we have recently been involved in, we can assume they are talking about us. When we are particularly insecure or passionate about a particular subject, just hearing a particular word or phrase can be enough to trigger a response, even if the original intention behind the words was nothing to do with what we heard! This is what happened to the disciples in the boat, they were feeling insecure because they had forgotten to buy some bread for the journey. Just the mention of the word yeast [leaven] from Jesus was enough to trigger this insecurity off, even though Jesus was talking about something completely different!
It shows that we have to be careful how we hear, particularly on subjects where our emotions run high. God has recently been teaching me on this subject; through this passage of scripture and through life experience. Hopefully the lesson is learned, but if not please point me back to this post!
A couple of things encourage me in this passage though. First it was all the disciples that reacted this way. It was not just Thomas or Judas who got the wrong end of the stick, and the others had a good laugh at their expense. They were all in the same boat (literally). We may have failings, in this or other areas, but it's always encouraging to know that you are not alone and others are working through the same issues. (1Co 10:13)
The other thing that blesses me greatly is that Jesus turns this misunderstanding around for good. It brings their insecurities to the surface so that Jesus can deal with them. Who knows if Jesus did not mention the "yeast" illustration deliberately for this purpose? Their initial reaction may not have been good, but God in his grace works all things for our good and greater benefit. They were much better off having unloaded their insecurities about their provision for the journey. I feel so much better off for having gone through a similar process too. God is so good!