Matthew 16:7 - Matthew Poole's English Annotations on the Holy Bible

Ver. 5-7. Mark saith, Mark 8:14-16, Now the disciples had forgotten to take bread, neither had they in the ship with them more than one loaf. And he charged them, saying, Take heed and beware of the leaven of the Pharisees, and of the leaven of Herod. And they reasoned among themselves, saying, It is because we have no bread. The disciples went into the ship without taking a due care for provision for their bodies, which they were sensible of when they came on shore on the other side. Christ happened in the mean time to give them a caution against the doctrine of the Pharisees, and Sadducees, and Herodians, which he properly expressed (though metaphorically) under the notion of leaven: this they understood not, but fancied that he had spoken this to them with reference to their want of bread, as if he had only given them warning, that for the making of bread to supply their necessity, they should not go to the Pharisees, or Sadducees, or Herodians, for leaven; or that they should not go to buy any bread of the Pharisees or of the Sadducees. So dull are we to understand spiritual things, and so soon had they forgot the doctrine which our Saviour had so lately taught them, Matthew 15:17,18, that those things which are foreign to a man, and come not out of his heart, do not defile a man, but those things only which proceed out of his heart.