Luke 17: 26: And as it was in the days of Noe, so shall it be also in the days of the Son of man.
God had established in His mind that there would be 120 years before the Flood would come (Genesis 6: 3: And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.), but this knowledge was not given to Noah. Noah was simply instructed by God to build an Ark and preach that the end of all flesh was at hand. Noah did not know the date when the judgment would come, but on May 10, A.M. 1656, God told Noah that in seven days the Flood would begin (Genesis 7: 1 – 4, 11 – 12), thus Noah knew that on May 17, the judgment would strike.
Jesus said that the same scenario would repeat in the last days. God has established in His mind when the Bride will be taken off the earth and when the Tribulation will begin, but this knowledge is not known to the Bride at present (Matthew 24: 36: But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.). However, as God supernaturally revealed to Noah the time for the judgment to begin, so it will be divinely revealed to the Bride when Her catching away will be shortly before it comes to pass.