'Thief in the night' is not related to The Rapture.

Dr. Andy Woods explains: “You know very well that the day of the Lord will come like a thief in the night.” (1 Thessalonians 5:2)

The correct intepretation: Thomas Ice, the Director of the pre-trib study group says, “The “thief” idea, in relation to a coming of christ, is used seven times only in the New Testament. (Matthew 24:43; Luke 12:39; 1 Thess 5:2, 4; 2 Peter 3:10; Revelation 3:3; Revelation 16:15). The thief in the night imagery never applies to the rapture. Such language usually is descriptive of unbelievers, and god's wrath or judgment related to the tribulation or second coming. The picture painted by a thief in the night, shows it is the unbeliever who is caught off guard, since he never really believes god is actually going to judge in history. The unbeliever thinks he has gotten away with ignoring God all his life, therefore, the lord is a non-factor, he thinks...” It should be noted that Paul clearly identifies his topic as “the day of the Lord,” which “will come just like a thief in the night” (1 Thess. 5:2b). The rapture is not spoken of as coming like a thief in the night. Verse three tells us it will be those who are saying, “‘Peace and safety!’ then destruction will come upon them suddenly like birth pangs upon a woman with child; and they shall not escape.” The unbelievers, who are said to be “of the darkness,” are the ones who will be caught off-guard and unprepared by God’s wrath during the tribulation. In fact, verse nine reminds believers that “For God has not destined us for wrath, but for obtaining salvation through our Lord Jesus Christ.” The means of deliverance from God’s wrath will be the rapture of the church, end of Chapter. 4.  But you, brothers and sisters, are not in darkness, so that the day would overtake you like a thief; (1 Thessalonians 5:4).