No sign for unbelief
Mark 8:10 And straightway he entered into a ship with his disciples, and came into the parts of Dalmanutha.
Dalmanutha is a town on the west side of the Sea of Galilee, near Magdala. Mary of Magdalene, from whom he cast out seven demons, would become one of his most faithful followers.
Mark 8:11 And the Pharisees came forth, and began to question with him, seeking of him a sign from heaven, tempting him.
Everyone knew of Jesus, his power from heaven. Still, as always there were the supposed religious people who did not believe in him. In every generation and today, people of self willed power, use their religion to condemn those who follow Jesus. They would not accept Jesus, they do not see him as from God. They do not see the evidence, they mockingly seek proof.
Luke 17:20 And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation:
Luke 17:21 Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you.
Mat 5:20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
It is by faith in Jesus that we enter his Kingdom.
Mark 8:12 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.
Mat 12:39 But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:
Mat 12:40 For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
Mark 8:13 And he left them, and entering into the ship again departed to the other side.
He left them who would not believe. Jesus stays with those who believe, for after he returned to the Father he gave us the Holy Spirit, our comforter. Jesus is always close to those who have faith in Him.