I don't understand, I thought what some are saying is that upon death on this planet the righteous go straight into heaven and the unrighteous go straight to hellfire? return with the Lord to where? if they are a spirit person why do they need a body?
return with the Lord to where?
"Brothers, we do not want you to be uninformed about those who sleep in death, so that you will not grieve like the rest, who are without hope. For since we believe that Jesus died and rose again, we also believe that God will bring with Jesus those who have fallen asleep in Him.
By the word of the Lord, we declare to you that we who are alive and remain until the coming of the Lord will by no means precede those who have fallen asleep. 16For the Lord Himself will descend from heaven with a loud command, with the voice of an archangel, and with the trumpet of God, and the dead in Christ will be the first to rise. 17After that, we who are alive and remain will be caught up together with them in the clouds to meet the Lord in the air. And so we will always be with the Lord."
"so that He may establish your hearts in blamelessness and holiness before our God and Father at the coming of our Lord Jesus with all His saints. Amen.
As the scripture above demonstrates, when the lord descends from heaven, he will bring with Him all the spirits of all those saints who have been with him in heaven. The Lord will cause their bodies to resurrect and their spirits/souls will be reunited with those resurrected bodies. Immediately after that, those believers who are still alive on earth will be changed into their immortal and glorified bodies right where they stand and will be caught up with those who will have just resurrected.
if they are a spirit person why do they need a body?
Regarding this, all I know is that the Lord resurrected in the same body that he was crucified in and we will also be resurrected and changed into those resurrected, immortal and glorified bodies. So, when we see him, we will be like him, in those upgraded, heavenly bodies.