“WATCH out, guard against the leaven of the Pharisees and the leaven of Herod.” (Mk 8,15) At first, the disciples of Christ thought Christ was referring to the fact that they only brought one loaf of bread.

So, Christ had to clarify it to them until they understood he was referring to the teachings and doctrine of the Pharisees and of Herod that, while containing some truth, did not capture the whole truth and, in fact, distorted the reality of things as designed by God, the Creator and the ever-provident Father of all.

We need to see to it that while we always have some use of some human teachings—like the many ideologies, philosophies, theologies, economic theories, etc.—we should rely first of all and always on our Christian faith that is now spelled out more concretely in the teachings of the Church.

It’s the word of God as revealed and embodied by Christ himself, and now taught by the Church with the authority given by Christ himself. To be sure, this teaching of Christ is the true leaven which is not simply a set of theories and indications, but also and mainly a spirit that was embodied by Christ himself and that he himself shares with us abundantly, if we only care to receive it.

This true leaven is nothing less than living our life entirely with Christ who is the pattern of our humanity, the savior of our humanity that is damaged by sin. It knows how to deal properly with any situation we can find ourselves in, whether good or bad according to our human criteria.

This true leaven is the very spirit of Christ. We have to realize that wherever we are, whatever we are doing, whatever may be our status, we have the duty to infuse this Christian spirit to everything that we handle. We have to be a leaven for the world.
Christ himself said so in no uncertain terms: “The kingdom of heaven is like leaven, which a woman took and hid in three pecks of flour until it was all leavened.” (Mt 13,33) Yes, the kingdom of heaven already starts here and should be on its way to its definitive state through our leavening presence and action.

We just have to make sure that we make ourselves genuine Christian leaven. That’s because Christ himself warned us of some false leaven. “Beware of the leaven of the Pharisees and the leaven of Herod,” he said. (Mk 8,15) This false leaven can refer to things like hypocrisy, self-righteousness, or any worldly spirit that is not from God.
This duty to be a true leaven for the world is actually very doable, because what is needed first of all is the intention to do so. We may not be doing something with big public significance or some external manifestation, but with the little ordinary things that we do everyday and done with faith and love for God and for others, we can already effectively leaven the world.

Let us sharpen our sense of communion among ourselves. Whatever we do, big or small, good or bad, will always have some effect on everybody else and on everything. It’s because of this communion among ourselves that can give a leavening effect on anything that we think, desire, say and do.

We should try our best that the leaven we give to the world is the right and true one, and not the false and deceptive ones that, sad to say, seem to be proliferating in the world today.