The Rapture is a theory based on the mystery of the Scriptures, and it's a very valid theory. It makes sense in that the Church is under grace during the current Church age and will be caught up before God turns His attention back to Israel for their final week (seven years) of punishment. Will it hold to be true? Only time will tell.
Jewish dispensation (Spring) ==> Gentile dispensation (Summer) ==> One more week of Jewish dispensation (Fall) ==> Return of Messiah Jesus to execute the winepress of the fierceness of God's wrath (Winter) ==> Millennial Kingdom (New Age)
Was the Gentile Church on earth when Jesus fulfilled the first 4 of the 7 Jewish feasts of the Lord? No (The Gentile Church really began when the Holy Spirit fell on Cornelius, his friends and family). Jesus fulfilled all the spring feasts, i.e., the Feast of Passover, the Feast of Unleavened Bread, the Feast of Firstfruits, the Feast of the Harvest (Pentecost). There are 3 more feasts to be fulfilled, which are all in the fall, i.e., the Feast of Trumpets, the Day of Atonement and the Feast of Tabernacles. It seems consistently logical that Jesus will fulfill them too. In God's seasonal calendar, the Gentile Church is in the summer season, and all the end-time signs indicate that we are at the end of the summer season. Fall is soon to begin. Will the Gentile Church be here on earth when Jesus begins to fulfill the last 3 Jewish feasts, beginning with the feast of Trumpets?
1 Thessalonians 4
[15] For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
[16] For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
[17] Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
[18] Wherefore comfort one another with these words.