'Sign' in the Bible

John came, and gave baptism in the waste land, preaching baptism as a sign of forgiveness of sin for those whose hearts were changed.

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

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.

Say when these things will be, and what will be the sign when these things are all about to be done.

But take care: for they will give you up to the Sanhedrins; and in Synagogues you will be whipped; and you will be taken before rulers and kings because of me, for a sign to them.

Now he who had been false to him had given them a sign, saying, The one to whom I give a kiss, that is he; take him, and get him away safely.