Mt 24: 37-44
For as it was in the days of Noah, so it will be at the coming of the Son of Man.
In (those) days before the flood, they were eating and drinking, marrying and giving in marriage, up to the day that Noah entered the ark.
They did not know until the flood came and carried them all away. So will it be (also) at the coming of the Son of Man.
Two men will be out in the field; one will be taken, and one will be left.
Two women will be grinding at the mill; one will be taken, and one will be left.
Therefore, stay awake! For you do not know on which day your Lord will come.
Be sure of this: if the master of the house had known the hour of night when the thief was coming, he would have stayed awake and not let his house be broken into.
So too, you also must be prepared, for at an hour you do not expect, the Son of Man will come.
Source: New American Bible
Catechism of the Catholic Church
673 Since the Ascension Christ’s coming in glory has been imminent, even though “it is not for you to know times or seasons which the Father has fixed by his own authority.” This eschatological coming could be accomplished at any moment, even if both it and the final trial that will precede it are “delayed”.