1 Thessalonians 5:2-3

for you know perfectly well that the day of the Lord [i.e., when He returns, See II Thess. 2:1-2] will arrive like a thief coming in the night.

Treasury of Scripture Knowledge

Summary

So Joshua came, and all the people of war with him, against them by the waters of Merom suddenly; and they fell upon them.

Bible References

Suddenly

1 Thessalonians 5:2
for you know perfectly well that the day of the Lord [i.e., when He returns, See II Thess. 2:1-2] will arrive like a thief coming in the night.