"No one knows about that day or hour,
not even the angels in heaven, nor the Son,
but only the Father. Be on guard! Be alert!
You do not know when that time will come.

It's like a man going away:
He leaves his house and puts his servants in charge,
each with his assigned task,
and tells the one at the door to keep watch.

"Therefore keep watch because you do not know
when the owner of the house will come back—
whether in the evening, or at midnight,
or when the rooster crows, or at dawn.
If he comes suddenly,
do not let him find you sleeping.
What I say to you, I say to everyone: 'Watch!' "

Mark 13:32-37:

For the Lord himself will come down from heaven,
with a loud command, 
with the voice of the archangel
and with the trumpet call of God,
and the dead in Christ will rise first.

After that, we who are still alive and are left
will be caught up together with them in the clouds
to meet the Lord in the air.
And so we will be with the Lord forever.

Therefore encourage each other with these words.
1 Thes 4:16-18