And when Jesus knew it ( καὶ γνοὺς ὁ ἰησοὺς)—literally and far more correctly, and Jesus perceiving it—he saith unto them, Why reason ye, because ye have no bread? Jesus perceived the direction in which their thoughts were moving, by the power of his divinity. It is as though he said, "Why reason ye because ye have no bread, as though I was referring to natural things, and speaking concerning bread for the body, and wishing you to be anxious about that; as though I could not provide that for you, if nccessary, just as easily here on the sea as I did just now in the desert?" Dr. John Lightfoot says, "The rule of the Jews was very strict as to the kind of leaven that was to be used; and the disciples supposed that our Lord was alluding to this when he cautioned them to beware of the leaven of the Pharisees." Perhaps they also thought that our Lord was conveying a silent reproof to them for not having brought a sufficient supply of bread with them. The whole incident, while it shows their transparent simplicity of character, exhibits also their dulness of apprehension.
Here St. Mark is as careful as St. Matthew to mention the details of the two miracles, even to the reference to the two kinds of baskets in which the fragments were gathered up. They had a distinct recollection of the facts, but they had failed to catch their spiritual import.