1 Cor 15:23 couldn't be any more clear. Jesus' resurrection is called "firstfruits" because He is the FIRST human to receive the resurrection glorified body.
Well (and I've tried to explain this in past post), I believe it is
verse 20 that speaks of
Jesus being "
firstfruit of those having fallen asleep" (Christ "has been raised
out-from [ek] the dead").
Next, skipping past verse 21, verse 22
goes on to speak of [
others, not Jesus] "For as
IN ADAM all die, even so
IN CHRIST shall [future tense] all BE MADE ALIVE" (Jesus was "conceived" in her/Mary by the Holy Spirit [Matt1:20], right? OR, would you say that Jesus Himself was "IN ADAM"?)
So, continuing further [next, and staying in the FLOW OF what has been said to this point] in the passage, v.23
continues on from there to be speaking of man who is born [originally] "IN ADAM" though the ones "IN CHRIST" are of course born again / -from above / saved persons (those having come to faith / believers). In other words, it is not back-tracking to speak of Jesus AGAIN, here (as though He were among those "IN ADAM").
And since James 1:18 says that
we are "a
KIND of
firstfruit," this means there is
*more than ONE "kind"... and this v.23b is speaking of THIS "firstfruit" (
connected with Christ, in the same way as
1Cor12:12 had just previously spoken of: "...and all the members of that ONE BODY, being many, are ONE BODY:
so also is THE CHRIST." This
isn't saying "all you Christians / believers are one body; and Jesus Himself is ANOTHER one body".
No.)
Then the next part of v.23 says, "afterward/then
[epeita - G1899 - 'only then'] those [plural] who are
OF Christ at His coming (I believe this refers to both
OT saints [Dan12:13 / Job19:25-27 / Jn11:24] AND
the saints who will DIE in the future Trib yrs [Rev20:4b, etc]), referring to His Second Coming to the earth point in time [not "our Rapture" point in the chronology]).
V.24 goes on to speak of "THEN [G1534 -
eita] the end..."
which I believe we agree on this point. (When "the last enemy that shall be destroyed is death" at the GWTj point in the chronology)
[
*note: the future "144,000" are called "firsfruit" also--but not the same group as "the Church WHICH IS HIS BODY" / US; I've pointed out the TWO mentions of "FIRSTFRUIT" in Leviticus 23... in past posts]
One important key, I think, is the word (enlarged above), "G1899 - epeita - ONLY THEN" (this wouldn't be said BY PAUL if it meant "only then" after Christ's OWN resurrection that had taken place well before Paul wrote this)