Translation
Then, if someone says to you, “Look, here is the Christ.
Or here.”
Do not believe.
Paraphrase
Then, if anyone says to you, “Look at this person, he seems to fulfill everything we are looking for in a Messiah figure. Or maybe this one over here.” Don’t believe them.
JESUS BEGINS TO MIX TWO THEMES
In my opinion, this is the point where Jesus begins to mix the two topics of the confirmation of the end of one age (AD 70), and His second coming yet in the future. From here on, some of what He says may apply to one time or the other, but much of it could refer to both.