1 Thessalonians 5:2-3

2You know very well about how the great day of the Lord will happen. That day will surprise people very much, like when a robber comes in the night.

3At that time, people will be saying, ‘We are safe and there is no trouble for us.’ But then, when they are not ready for it, great punishment will suddenly happen to them. It will be impossible for them to run away. Pain will suddenly come to them, like a woman who is giving birth to a baby.