As mentioned in the Bible, what will be the "sign" of Jesus when He reappears for His 2nd coming?

It would be helpful if you could provide a Bible quote about "the sign of Jesus" at his second coming. Meanwhile, I found this:

God would often use signs (or miracles) in the Bible to authenticate His chosen messenger. The Lord provided Moses with several miraculous signs in order to prove to others that he was appointed by God (Exodus 4:5-9; 7:8-10; 19-20). God sent down fire on Elijah’s alter during Elijah’s contest with the prophets of Baal (1 Kings 18:36-39). He performed this miracle to prove that the God of Israel was the one true God. Jesus himself would perform many miracles (or “signs”) to demonstrate His power over nature (Matthew 4:23; Mark 6:30-44; Luke 8:22-24; John 6:16-24). The “sign of Jonah” would turn out to be Jesus’ greatest miracle of all. Jesus’ resurrection from the dead would be God’s chief sign that Jesus was Israel’s long awaited Messiah (Acts 2:23-32) and establish Christ’s claims to deity (Romans 1:3-4).

Personally, I think if an unbelieving world needs a physical sign to announce the second coming of Christ Jesus, it will be too late for them. Jesus said even if someone came back from the dead, people would still not believe. The Bible tells us his second coming will be like lightning which travels across the sky, that he will return in great power and glory and accompanied with all the angelic heavenly hosts. Every eye will see. But it will be too late for unbelievers to change their mind. Jesus will have gathered his people by then.

Matthew 24 and 25 gives a list of events taking place in the last days. There is solid evidence over the past century these events have marked our time. Just like the apostles who were asking about this time, we can listen to Jesus' words and know that the time is limited.

Please examine the following two links. You will find more information in the rest of the links at this site.

According to the bible it should already have happened.

This is what Jesus says directly after he describes the signs:

Luke 21:32 Verily I say unto you, This generation shall not pass away, till all be fulfilled.

Jesus will be back on earth within one generation, through the exact time is never revealed.

As for the signs. Luke 21. Readers digest version:

Many shall come in my name, saying, I am Christ.

Ye shall hear of wars and commotions.

Nation shall rise against nation, and kingdom against kingdom.

Great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven.

Ye shall be betrayed both by parents, and brethren, and kinsfolks, and friends.

Ye shall see Jerusalem compassed with armies.

There shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring.

he'll be coming round the mountains when he comes like a thief in the night and the heavens will pass away with a great noise the elements will melt with fervent heat the earth, its works,and all that is in it will be burned up 2 peter 3:10 except the mountain thing thought it could use some humor gets ugly shortly after

Most English versions of the Nicene Creed in current use include the following statements: "..he ascended into heaven and is seated at the right hand of the Father. He will come again in glory to judge the living and the dead, and his kingdom will have no end. ... We look for the resurrection of the dead, and the life of the world to come."

It'll probably be a hi-def LED sign. Those are pretty common these days.

Rainbow?