Don't believe it if anyone says "look! Here is the Christ!" Or "there He is!"
False prophets and false christs are going to rise and show great signs and wonders to deceive the elect if possible.
He is telling us ahead of time.
Don't go out, don't believe it.
When Jesus comes it will be like lightening.
Lightening is fast and quick and you won't miss it!
I love how Jesus knows the future and warns His believers ahead of time to be watchful of those that would claim to be Him. He has warned us.
This is why we need to be solid in reading the Word. God has given us so much direction for us in it. He knows how easy it would be to stumble. And especially considering the Jews who didn't accept Him are still looking and waiting for their Savior... It could be possible to become deceives or filled with doubts. Be solid and stand strong in the truth.