Mark 8:12

12 And he was very sad in spirit, and said, Why is this generation looking for a sign? truly, I say to you, No sign will be given to this generation.

Mark 8:12 Meaning and Commentary

Mark 8:12

And he sighed deeply in his Spirit
In his human soul; and which shows that he had one, and was subject to grief and sorrow, and all passions and infirmities, excepting sin. This deep sigh was on account of the hardness of their hearts, the malignity of their minds, and insincerity of their intentions; who had no view to come at truth by this inquiry, but to ensnare him:

and saith, why doth this generation seek after a sign?
when so many have been shown among them, and they will not believe:

verily I say unto you, there shall no sign be given to this
generation:
such as they desired; namely, one from heaven. The Evangelist Matthew adds, "but the sign of the Prophet Jonas"; (See Gill on Matthew 16:4), (See Gill on Matthew 12:40).

Mark 8:12 In-Context

10 And he got into the boat with his disciples straight away, and came into the country of Dalmanutha.

11 And the Pharisees came out and put questions to him, requesting from him a sign from heaven, testing him.

12 And he was very sad in spirit, and said, Why is this generation looking for a sign? truly, I say to you, No sign will be given to this generation.

13 And he went away from them, and again got into the boat and went across to the other side.

14 And they had taken no thought to get bread; and they had only one cake of bread with them in the boat.