Those who espouse to a pretribulation view of the rapture typically hold that the rapture will be “secret,” in the sense that no unbeliever will witness the event because it happens so quickly. The Scriptural justification for this view is said to be 1 Corinthians 15:51-52.
Behold! I tell you a mystery. We shall not all sleep, but we shall all be changed, 52 in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed.
If this passage teaches a secret rapture of the church, it would be unique among the raptures recorded in Scripture. All other raptures were witnessed by those who remained on the Earth. Enoch was raptured to heaven (Gen5:24). While we are not told of any particular person who witnessed the event, it must have been witnessed by someone, otherwise people could not have known that God took him. Elijah’s rapture was witnessed by Elisha (2 Kings 2:1-12). Jesus’ rapture was witnessed by the apostles (Acts 1:9-11). The rapture of the Two Witnesses will be witnessed by their enemies (Rev 11:3-12). Why would all other raptures in the Bible be public, but the rapture of the church be secret? If we could develop any Biblical precedent for the speed of the church’s rapture, it would appear that it will be slow enough for others to witness it.