What is the key sign of the coming of Jesus and the End of the World?

What is the key sign of the coming of Jesus and the end of the world?

Jesus says: “Take heed that no man deceive you. For many shall come in my name, saying, ‘I am Christ;’ and shall deceive many” (Matthew 24:4–5). 

What then is the key sign?

Jesus says: “When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand)” (Matthew 24:15).

"And when ye shall see Jerusalem compassed with armies, then know that the desolation thereof is nigh. Then let them which are in Judæa flee to the mountains; and let them which are in the midst of it depart out; and let not them that are in the countries enter thereinto. For these be the days of vengeance, that all things which are written may be fulfilled” (Luke 21:16-22).

“And they shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled.

And 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;

Men’s hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken.

And then shall they see the Son of man coming in a cloud with power and great glory” (Luke 21:24-27).