'Sign' in the Bible

Then answered him some of the scribes and Pharisees, saying, Teacher, we desire to see a sign from thee.

But he, answering, said to them, A wicked and adulterous generation seeks after a sign, and a sign shall not be given to it save the sign of Jonas the prophet.

And the Pharisees and Sadducees, coming to him, asked him, tempting him, to shew them a sign out of heaven.

A wicked and adulterous generation seeks after a sign, and a sign shall not be given to it save the sign of Jonas. And he left them and went away.

And as he was sitting upon the mount of Olives the disciples came to him privately, saying, Tell us, when shall these things be, and what is the sign of thy coming and the completion of the age?

And then shall appear the sign of the Son of man in heaven; and then shall all the tribes of the land lament, and they shall see the Son of man coming on the clouds of heaven with power and great glory.

Now he that delivered him up had given them a sign, saying, Whomsoever I shall kiss, he it is: seize him.