Mark 13:29-33

In the same way, when you see all these things taking place, you can know that his return is very near, right at the door. I tell you the truth, this generation will not pass from the scene before all these things take place. Heaven and earth will disappear, but my words will never disappear. “However, no one knows the day or hour when these things will happen, not even the angels in heaven or the Son himself. Only the Father knows. And since you don’t know when that time will come, be on guard! Stay alert!