I Thessalonians 5:3-5

"When they are saying, Peace and security, then unexpected ruin will fall on them, just like the birth pains of one having a child. And escape will be impossible." (I Thessalonians 5:3)

When the world thinks that war is at an end, and there is security then the end will come. They will be demolished and it will be impossible for those without Christ to escape.

"But you, brothers, are not in darkness that the day surprise you like a thief." (I Thessalonians 5:4)

Christians should not be surprised by the Day of the Lord. We know it is coming. And as it gets closer, the signs will become more and more clear to us.

"For in every way, you all are sons of the light and sons of the day. We are not of the night or of the darkness." (I Thessalonians 5:5)

Paul contrasts those in the light with those in the dark. Christians are in the light; they have the revelation of God and the insight of the indwelling Holy Spirit. Those without Christ are in darkness. They do not understand clearly the flow of history, nor do they expect what is coming.