Matthew 24 highlights the uncertainty of the timing of the second coming of Jesus Christ and the importance of being watchful and ready for His return.
Jesus uses the illustration of the days of Noah, when people were caught unaware by the flood...Even though the preaching had happened and the warning had been given.
When Jesus returns people will be going about their daily activities and He will return...even thought the message has gone forth...some will still reject.
This passage shows the need for believers to be prepared, and living in anticipation of the imminent return of Christ.