1 Thessalonians 5:3
For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape. (1 Thessalonians 5:3)
Shall not escape.
 Rather, “shall in no wise escape,” no more than a woman can escape the birth of her child. Thus the apostle stresses the inevitability of the destruction that will come upon those who have rejected their Saviour. Paul appears to have had Christ’s own words (Luke 21:34-36) in mind as he wrote these thoughts to the Thessalonians (1 Thess. 5:3).
As travail.
Or, “even as birth pang.” Childbirth cannot be called an unexpected event, but the onset of labor, with its pains, comes suddenly. Paul uses the figure to illustrate the suddenness of the last-day catastrophes.
Destruction.
Gr. olethros, “destruction,” “death,” “ruin,” a noun derived from the verb ollumi, “to destroy.” Thus the phrase “sudden destruction” implies that “the day of the Lord” will bring unexpected catastrophe to the unbelieving world.
Sudden.
 Gr. aiphnidios, “unexpected,” “unforeseen,” “sudden.” The word occurs in the NT only here and in Luke 21:34.
Peace and safety.
 These words, spoken by those who have not prepared for their Lord’s return, refer to inner tranquillity and external security, and reveal the satisfied state of the speakers’ minds. The calm is unjustified, for disaster is close at hand, and the unbeliever should really learn from the Christian, who is watchfully ready for last-day events. The Scriptures teach that the time immediately preceding Christ’s appearing will be one of universal distress (see on Luke 21:25, 26). See below on “sudden” and “destruction.”
When they shall say.
 Or, “whenever they may say.” Paul does not specifically identify who “they” are, but it is clear from the context (vs. 4-6) that he is referring to unbelievers. Although the apostle does not specifically state the time when the worldlings utter the words attributed to them, it is clear from the remainder of the verse that the words must be spoken immediately prior to Christ’s coming.
Cometh.
 Gr. ephistēmi, “to stand over,” “to stand by,” “to approach,” especially used of sudden appearances (Luke 2:9; 20:1; 24:4; Acts 6:12; etc.; cf. on Acts 12:7).