The reference to a thief in the night has its roots in the teaching of Jesus Christ (see Matthew 24:43–44; Luke 12:39–40). This reference can also be found elsewhere in the New Testament (1 Thessalonians 5:2; Revelation 3:3; Revelation 16:15).1 The basic idea is that just as the arrival of a thief is unexpected, so the return of the Lord will be unexpected. No one knows the day or the hour when Christ will return (Matthew 24:36).
10 But the day of the Lord will come like a thief, and then the heavens will pass away with a roar, and the heavenly bodies will be burned up and dissolved, and the earth and the works that are done on it will be exposed.