Hebrews 6:2 lists resurrection and judgment as elementary or basic doctrines of our Christian faith. Resurrection and judgment are key themes of the Appointed Day. Hebrews 9:27 tells us about physical death: "And it is appointed for men to die once, but after this the judgment." The Bible is clear: there is no such thing as reincarnation.
Genesis 2:17 gives us a clue about what is typically called spiritual death. "But of the tree of the knowledge of good and evil you shall not eat, for in the Day that you eat of of it, you shall surely die." Physical death is being separated from our physical bodies; spiritual death is being separated from intimate communion with God the Creator, the source of life.
Every human is first and foremost a spirit being. A spirit doesn't die; it is eternal. Adam and Eve didn't immediately die physically when they ate of the tree. But they were separated from God. Sin creates a gulf between fallen humans and the holy God. Because of His great love, God made a way to bridge that gulf through Jesus -- what is commonly called the new birth or being born again.
Part of our salvation includes the hope of glory described in John 6:40. "And this is the will of Him who sent Me, that everyone who sees the Son and believe in Him may have everlasting life; and I will raise him up at the Last Day."
Resurrection means to be lifted up, to be raised up, to be perfected, and to be completed. Every believer shall be resurrected at the Last Day. As that Day dawns, Christ will return and gather us to Him at the rapture, and take us to Father's House in Heaven (our prepared place). We receive our glorified, immortal bodies, and we receive our next assignment as part of the heavenly court at the right hand of the Father.
This is called the firstfruits resurrection (1 Cor 15:29). Christ was the first of the firstfruits (plural) when He arose on the 3rd day. Romans 8:29 explains that we are rest of the firstfruits: "For whom He foreknew, He also predestined to be conformed to the image of His Son, that He might be the firstborn among many brethren." James 1:18 calls us "a kind of firstfruits of His creatures." The Apostle Paul explains the order of our 3rd Day firstfruits resurrection in 1 Thess 4:13-18. The dead in Christ arise first, then those who are alive at His coming.
Firstfruits refers to a special offering brought to the Lord in the Old Testament before the first harvest could begin (Lev. 23). The offering reminded the people of their bondage in Egypt, God's deliverance, and the Promised Land. Unlike the other offerings, this was set apart solely for the Lord.
Our firstfruits resurrection happens at the start of Christ's 1,000-year reign (the 7th Day), for the Head and the Body must be fully complete and together in Heaven in order to reign as joint-heirs. This doesn't take away from Christ in any way, for He always has the preeminence (Colossians 1:18). It shows His great love for His beloved Bride and the amazing grace of being "in Christ."