Martyrdom
The effect of such worldwide preaching by invincible and dedicated servants of God will be stupendous.
Uncounted multitudes will be saved. This is the same group mentioned in Rev. 6:9. The mysterious disappearance
of millions of Christians at the rapture would doubtless leave
an indelible impression on people. They [those left behind] would soon realize that the common denominator of those who had disappeared
was their faith in Jesus Christ! [They then accept the gospel.] We see these saved multitudes in heaven
because they have been killed by the antichrist. To accept Christ as
Saviour during the tribulation period would usually mean martyrdom. (A Pictorial Guide to Bible Prophecy, p. 292)