Adam Clarke's Commentary on the Bible - Matthew 16:7
They reasoned - For, as Lightfoot observes, the term leaven was very rarely used among the Jews to signify doctrine, and therefore the disciples did not immediately apprehend his meaning. In what a lamentable state of blindness is the human mind? Bodily wants are perceived with the utmost readiness, and a supply is sought with all speed. But the necessities of the soul are rarely discovered, though they are more pressing than those of the body, and the supply of them of infinitely more... read more
Adam Clarke's Commentary on the Bible - Matthew 16:6
Beware of the leaven - What the leaven of Pharisees and Sadducees was has been already explained, see Matthew 16:1 . Bad doctrines act in the soul as leaven does in meal; they assimulate the whole Spirit to their own nature. A man's particular creed has a greater influence on his tempers and conduct than most are aware of. Pride, hypocrisy, and worldly-mindedness, which constituted the leaven of the Pharisees and Sadducees, ruin the major part of the world. read more