This passage of scripture identifies a multitude of people who have resurrected bodies just like our Lord Jesus Christ. These real people were alive at the rapture when Christ took His Bride. They are identified in Revelation 7:9-17, as those who refused to take the mark of the beast and were slain for their witness of Christ. These are the martyred saints who were killed during the tribulation period and their number is said to be so great that no man could number them.
When Christ comes in the clouds of glory to rule and reign on earth they will be resurrected. As mentioned above, they are promised a place in the millennial reign of Christ, but what their duties will be is uncertain, but they will take part. Some hold to the view that they will act as servants in the millennium temple due to their description in Revelation 7:15 which states, Therefore are they before the throne of God, and serve him day and night in his temple: And he that sitteth on the throne shall dwell among them.
Whatever their position, it is certain that they will have a special place in His kingdom, for He will dwell among them.
Those people who have accepted Christ as Savior during the approximately 2500 years of the Church Age are referred to by Christ as His Church, His "Bride", and Scripture clearly spells out what their future is during the Tribulation in Heaven and during the millennium; however, they are a separate group of saints than those who miss the Rapture because they are not saved at that time and who receive Christ as Savior during the Tribulation.
Here is the verses for the rapture and the one and only first resurrection
1Thes 4:13-17 13 But I do not want you to be ignorant, brethren, concerning those who have fallen asleep, lest you sorrow as others who have no hope. 14 For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus. 15 For this we say to you by the word of the Lord, that we who are alive and remain until the coming of the Lord will by no means precede those who are asleep. 16 For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. And the dead in Christ will rise first. 17 Then we who are alive and remain shall be caught up (raptured) together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord. (NKJ)