When Jesus Christ was born, very few knew that the Savior had come to the world was.

When he returns there will be no doubt about who he is. Nobody knows exact time when Jesus Christ will come again.

Matthew 24:

36 “But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father. ”

The Lord has given us a reference to the time of his coming through a parable:

Mark 13:
“28 Now learn this lesson from the fig tree: As soon as its twigs get tender and its leaves come out, you know that summer is near.
29 Even so, when you see these things happening, you know that it[a] is near, right at the door.”

and

21 At that time if anyone says to you, ‘Look, here is the Messiah!’ or, ‘Look, there he is!’ do not believe it.
22 For false messiahs and false prophets will appear and perform signs and wonders to deceive, if possible, even the elect.
23 So be on your guard; I have told you everything ahead of time.

Matthew 24:
“42 “Therefore keep watch, because you do not know on what day your Lord will come.
43 But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into.
44 So you also must be ready, because the Son of Man will come at an hour when you do not expect him.”

All Bible references through Bible gateway.com,
compiled by Jehoschua Eugen Senn, 8315 Lindau ZH, the returned Christ.