'Sign' in the Bible

This is the sign to you: you will find a baby wrapped in strips of cloth, lying in a feeding trough."

and Simeon blessed them, and said to Mary, his mother, "Behold, this child is set for the falling and the rising of many in Israel, and for a sign which is spoken against.

Others, testing him, sought from him a sign from heaven.

When the multitudes were gathering together to him, he began to say, "This is an evil generation. It seeks after a sign. No sign will be given to it but the sign of Jonah, the prophet.

For even as Jonah became a sign to the Ninevites, so will also the Son of Man be to this generation.

They asked him, "Teacher, so when will these things be? What is the sign that these things are about to happen?"