Mark 8:15

‘And he charged them saying, “Take notice. Beware of the leaven of the Pharisees and the leaven of Herod ”.'

The situation drew from Jesus one of His enigmatic sayings. As He saw them worrying about shortage of bread He still remembered the Pharisees' demand for a sign, which had demonstrated their spiritual bankruptcy. He did not want His disciples to be in the same position. Rather than worrying about bread they should be concerned about the false teaching that might deceive them and lead them astray. So their concern should not be about lack of bread but about ensuring that they had the true bread, the genuine sign of which they had been privileged to witness. They had to ensure that they avoided the leaven of the Pharisees and the leaven of Herod. In other words they were to avoid being led astray by religious ritual and pious pronouncements or by worldly advancement, seeking rather to enjoy the bread of life. He may also have had in mind their need to avoid the desire of the Pharisees for spectacular ‘signs'.

The feeding of the crowd should have demonstrated to them that He was here, not in order to raise an insurrection, or to be a sign-giver, but so as to be a Messiah Who would feed men's hearts with Himself as the Bread of life, and that that was therefore what should now be their main concern. The Pharisees offered the way of ritual and religiosity, and even of passive resistance against Rome, Herod offered the way of compromise, and of cooperation with Rome. But what they should be concerned about was that they received His teaching truly unaffected by any such false ideas. He wanted them to be free from political ideas so that they could concentrate on what was important, the feeding of the souls of men.

‘Leaven.' Dough that had been left and had fermented. It was thus permeated with corruption.

Matthew interprets ‘leaven' as ‘the teaching of --' (Mark 16:12). Luke interprets it as ‘hypocrisy' (Luke 12:1). Either way it was corrupted bread. It refers to the inner thinking of the Pharisees and Herod, truth twisted into their own kind of falsehood by the Pharisees, and putting earthly pleasure, power, gain and prestige before godliness by Herod. They had to beware of both ritualism and worldliness.

This is confirmed by the use of the idea of leaven in 1 Corinthians 5:6 and Galatians 5:9, and in Rabbinic Judaism where leaven was a common metaphor for the evil tendency in man. Thus Jesus was warning them against allowing their thoughts to be turned aside from concentration on Him as the source of life towards either legalistic practises and the traditions of men, which twisted the truth and resulted in hypocrisy, or towards grasping, worldly, ungodly behaviour which resulted in the same. Had Judas heeded this he would not have betrayed Jesus. Perhaps Jesus was in fact already aware that some of His disciples were being approached privately by representatives of both the Pharisees and Herod, and were even possibly a little shaken by it. For they had grown up respecting the Pharisees and fearing Herod.