Someone asks, “But… What about those signs? Maybe no one now knows when that day will be, but if You told us what the signs will be, we’ll be able to detect them, and then we’ll at least know when the day is approaching.” The Lord already spoke to this question, right here in Matthew 24:
“For as [in] the days of Noah…they were unaware until the flood came…, so will be the coming of the Son of Man” (37-39).
“…for you do not know on what day your Lord is coming” (42).
“…for the Son of Man is coming at an hour you do not expect” (44).
In other words, the Lord, Himself, declared that the day of His (one and only) return was then, is now, and always will be, utterly unknowable and wholly undetectable.
Think about it: Jesus just spent thirty-one verses talking about the signs of the day, and then follows up with another fifteen verses (and at least half of the next chapter) intimating that there will be no signs of the day; thirty-one verses about what to expect leading up to the day, trailed by the proclamation that the day will be completely unexpected and unforeseeable; thirty-one verses about how to know when the day is near, finished off with an extended illustration demonstrating that there is no way to know when the day is near!
Clearly, the Lord is speaking of two different days in Matthew 24.