Mark 6:52

because they had not understood [the miracle of] the loaves [how it revealed the power and deity of Jesus]; but [in fact] their heart was hardened [being oblivious and indifferent to His amazing works].

Mark 3:5

After looking around at them with anger, grieved at the hardness and arrogance of their hearts, He told the man, “Hold out your hand.” And he held it out, and his hand was [completely] restored.

Mark 8:17-21

Jesus, aware of this [discussion], said to them, “Why are you discussing [the fact] that you have no bread? Do you still not see or understand? Are your hearts hardened?

Isaiah 63:17


O Lord, why do You cause us to stray from Your ways
And harden our heart from fearing You [with reverence and awe]?
Return for Your servants’ sake, the tribes of Your heritage.

Matthew 16:9-11

Do you still not understand or remember the five loaves for the five thousand, and how many baskets you picked up?

Mark 7:18

And He said to them, “Are you, too, so foolish and lacking in understanding? Do you not understand that whatever goes into the man from outside cannot defile and dishonor him,

Mark 16:14

Later, Jesus appeared to the eleven [disciples] themselves as they were reclining at the table; and He called them to account for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen [from death].

Luke 24:25

Then Jesus said to them, “O foolish men, and slow of heart to trust and believe in everything that the prophets have spoken!

Romans 11:7

What then? Israel failed to obtain what it was seeking [that is, God’s favor by obedience to the Law], but the elect [those chosen few] obtained it, while the rest of them became hardened and callously indifferent;

Treasury of Scripture Knowledge

Summary

For they considered not the miracle of the loaves: for their heart was hardened.

General references

Bible References

They

Mark 7:18
And He said to them, “Are you, too, so foolish and lacking in understanding? Do you not understand that whatever goes into the man from outside cannot defile and dishonor him,
Mark 8:17
Jesus, aware of this [discussion], said to them, “Why are you discussing [the fact] that you have no bread? Do you still not see or understand? Are your hearts hardened?
Matthew 16:9
Do you still not understand or remember the five loaves for the five thousand, and how many baskets you picked up?
Luke 24:25
Then Jesus said to them, “O foolish men, and slow of heart to trust and believe in everything that the prophets have spoken!

Their

Mark 3:5
After looking around at them with anger, grieved at the hardness and arrogance of their hearts, He told the man, “Hold out your hand.” And he held it out, and his hand was [completely] restored.
Mark 16:14
Later, Jesus appeared to the eleven [disciples] themselves as they were reclining at the table; and He called them to account for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen [from death].
Isaiah 63:17

O Lord, why do You cause us to stray from Your ways
And harden our heart from fearing You [with reverence and awe]?
Return for Your servants’ sake, the tribes of Your heritage.

General references

Matthew 15:16
And He said, “Are you still so dull [and unable to put things together]?