They were reasoning among themselves and saying, “He says this because we have no bread.”
The disciples’ response shows how slowly the human mind rises from the material to the spiritual. Christ was speaking about “leaven” as an image of an inner and spiritual danger, but the disciples immediately connected it with their lack of bread. This shows that without spiritual watchfulness a person can perceive even the Lord’s word within the limits of everyday concerns. When the heart is weighed down with earthly cares, even heavenly teaching can be misunderstood. Their way of thinking also reveals how material problems can cover a person’s spiritual sight, not allowing one to notice the dangers. A person may worry about the lack of bread, yet not notice the intrusion of the dangers of false teaching or the corruption of the heart. This verse shows that a person’s inner condition affects the ability to understand God’s word with discernment.