You do not know on what day your Lord will come.
—Matthew 24:42
“No one knows about that day or hour, not even the angels in heaven, nor the Son, but only the Father … So you must be ready, because the Son of Man will come at an hour when you do not expect him” (Matt. 24:36, 44).
Jesus is coming; that is certain. Nobody knows when; that is equally certain.
We’re nesting here in a short snippet of time. The Bible pictures earthly life as a mist that appears briefly and then vanishes; a fleeting shadow; a passing breeze; grass that withers and flowers that fall.
There will be only one living generation when he returns, but every generation should live in a could-be-any-moment mode. “Keep watch, because you do not know on what day your Lord will come.”
The fact of his return is certain;
the when of his return isn’t.