While all Christians are followers of Christ, not all followers of Christ are Christians. This is because the original status of the word Christian means 'anointed-one'. So as the Apostle Paul informs us:
“Therefore only if you are of the Anointed, are you actually Abraham’s seed, heirs and instrument of the promise.” (Galatians 3:29) NMTCS These words of Paul confirm the words of Jesus when talking to this select group said: “Fear not, little flock, for it is your Father’s good pleasure to give you the Kingdom.” (Luke 12:32) 21st Century King James Version (KJ21)
So these are the Christians who inherit immortality in the heavens along with Christ as later confirmed: "Revelation 20:6 Happy and holy is anyone having part in the first resurrection; over these the second death has no authority, but they will be priest of God and of the Christ, and will rule as kings with him for the thousand years.” (NMTCS)
These are the ones who have received the spirit of adoption, because they like Christ; are raised up as immortal spirit creatures (John 8:14-17) while the rest of all mankind will receive and earthly resurrection as confirmed in Martha's words to Jesus regarding the raising of her dead brother in reference to the general resurrection: "I know he will rise in the resurrection on the last day." (John 11:24)
These scriptures categorize both the heavenly [1st resurrection] and the earthly [2nd resurrection].
The heavenly sons of adoption and the earthly salvation of the rest of mankind who avoid the 'second death' at the end of the Sabbath Millennium. (Revelation 21:
Yours in Truth,
Alexander