That is what the pure apostles asked during their dialog with Jesus. What they were concerned about was the when? And about the signs of the Lord’s coming?
Here our master Jesus corrects the apostle’s path, and changes their
thinking from the periodic entities. He warns them about dangerous
matters, which should be on their minds. Look at yourselves stay up
late. Be stead fast in the faith, as a lot will be misguided. There
will be false prophets and false teachers in the name of Jesus. They
will misguide a lot. Hopefully that, when the Son of man comes, He
might find faith on earth.