There will be three kinds of people living in our world when the Lord returns for His Church: those who long for the Rapture of the Church (1 Jn. 3:2-3); those who are ignorant concerning the Rapture of the Church (1 Thes. 4:13-18); and those who scoff at the idea of the Rapture of the Church (2 Pet. 3:3-4). For those of us who eagerly await Christ's return for us, we see the "signs of the times" and we know it could happen at any moment (Matt. 16:1-3; 1 Cor. 15:51-52). For those who are born again but have not been taught the Word rightly divided (2 Tim. 2:15), they are in for a wonderful surprise. For those who deny the Bible as God's revelation to man, and therefore are not saved (Rom. 10:17), who mock us for our hopeful anticipation of His return for us (Jude 1:11-19), and who fail to heed our warning, they are destined for tribulation such as the world has never known (Matt. 24:21).
The key passage concerning the Rapture of the Church is found in 1 Thessalonians 4:13-18, which says,
"But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope. For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with Him. 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. 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: 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. Wherefore comfort one another with these words."
Some students of the Bible confuse this passage with the Second Coming of Christ to establish His Millennial Kingdom. But notice that in the Rapture, the Lord returns for His Church and we will rise to meet Him in the air. At His Second Coming, the Lord will descend upon the Mount of Olives (Zech. 14:4). At the Rapture, believers are removed, while at His Second Coming, unbelievers are removed (Matt. 25:13-46). At the Rapture, His removal of the Church will happen so quickly that no one will know it happened (1 Cor. 15:52), while at His Second Coming, the whole world will see it (Matt. 24:27). The reason for the Rapture is for Christ to receive His Bride, the Church (Jn. 14:1-3; 2 Cor. 11:2). The reason for His Second Coming is to fulfill the prophecies that He will rule forever on the throne of His father David (Isa. 9:6-7; Lk. 1:31-33).
We must study God's Word in order to understand what He wants us to know, and in so doing, please Him (2 Tim. 2:15). "I would not have you to be ignorant brethren" (Rom. 1:13; 11:25; 1 Cor. 10:1; 12:1; 2 Cor. 1:8; 1 Thes. 4:13; 2 Pet. 3:8). God bless you as you study, believe, and obey His Holy Word!