'Sign' in the Bible

The Pharisees came out and began to argue with Him, seeking from Him a sign from heaven, to test Him.

Sighing deeply in His spirit, He *said, “Why does this generation seek for a sign? Truly I say to you, no sign will be given to this generation.”

“Tell us, when will these things be, and what will be the sign when all these things are going to be fulfilled?”