'Sign' in the Bible

Then certain of the scribes and Pharisees answered, "Teacher, we want to see a sign from you."

But he answered them, "An evil and adulterous generation seeks after a sign, but no sign will be given it but the sign of Jonah the prophet.

The Pharisees and Sadducees came, and testing him, asked him to show them a sign from heaven.

An evil and adulterous generation seeks after a sign, and there will be no sign given to it, except the sign of the prophet Jonah." He left them, and departed.

As he sat on the Mount of Olives, the disciples came to him privately, saying, "Tell us, when will these things be? What is the sign of your coming, and of the end of the age?"

and then the sign of the Son of Man will appear in the sky. Then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of the sky with power and great glory.

Now he who betrayed him gave them a sign, saying, "Whoever I kiss, he is the one. Seize him."