The kingdom of heaven

I teach at a Christian high school in the mornings, and on Wednesdays we have a Chapel service to start the day. Last week Eric F. taught from Matthew 13:33

Another parable He spoke to them: “The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened.”

This parable is very convicting. If we, believers, are the leaven, and the meal is the people around us, then Christ has "hid" us in our neighborhoods, in our jobs, in our walks of live. It does not take much leaven to affect a huge batch (possibly 22 liters) of meal. Are we affecting all "the meal" around us?