Matthew 16:5-7 - Be careful!

16:5,6

This incident shows clearly that the feeding of the 4000 and 5000 were separate incidents. More importantly, it shows the slowness of the disciples, or rather the human propensity to focus on things that don’t really matter. Jesus warns them to beware the yeast of the Pharisees and the Sadducees. What He meant was there teachings, in particular the underlying attitudes and assumptions, were dangerous and could work their way through eventually contaminating everything. The odd item or two of Pharisaical or  Sadducee teaching might seem quite sensible and certainly harmful, but then it can permeate its way to infect all sorts of things. Notice also that Jesus talks about the Pharisees and the Sadducees. These two groups were quite different and were usually at war with each other. The answer to one wrong teaching is not to go to the other extreme, which is what we usually do!

16:7

While Jesus was talking about important spiritual matters, the disciples' mind went elsewhere! They thought it was because they hadn’t brought any bread. Now just consider how ridiculous this thinking was. How was yeast going to help them? They could hardly bake a loaf of bread while they were on the boat. So why did their minds go there? Maybe it was guilt or the fear of making a mistake, so we imagine every possible way in which things can go wrong. Our minds are very prone to focus on things that do not matter.