Mark 8:21
"And he said unto them, How is it that ye do not understand?"
Cross References (ranked by relevance)
For they considered not the miracle of the loaves: for their heart was hardened.
Understand, ye brutish among the people: and ye fools, when will ye be wise?
I speak to your shame. Is it so, that there is not a wise man among you? no, not one that shall be able to judge between his brethren?
Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father?
Awake to righteousness, and sin not; for some have not the knowledge of God: I speak this to your shame.
And when Jesus knew it, he saith unto them, Why reason ye, because ye have no bread? perceive ye not yet, neither understand? have ye your heart yet hardened?
And he sighed deeply in his spirit, and saith, Why doth this generation seek after a sign? verily I say unto you, There shall no sign be given unto this generation.
He answereth him, and saith, O faithless generation, how long shall I be with you? how long shall I suffer you? bring him unto me.