Mark 4:29

4:29 And when the grain is ripe, he sends in the sickle because the harvest has come.”

Mark 6:52

6:52 because they did not understand about the loaves, but their hearts were hardened.

Mark 10:5

10:5 But Jesus said to them, “He wrote this commandment for you because of your hard hearts.

Mark 15:10

15:10 (For he knew that the chief priests had handed him over because of envy.)