What people don't understand is that as long as there was Christ there's been the church in Him. He never existed without being it's Head.
That's absolutely True Brother, Christ's Church was In Him, Israel Is. 49:3, our Head from all eternity, or before the World began Eph. 1:4; 2 Tim. 1:9.
The Old Testament Saints are part of Christ Body the Church, or they will not partake of the resurrection in the Last day which they had an eye to. Christ is the firstfruits 1 Cor 15:12-23
12 Now if Christ be preached that he rose from the dead, how say some among you that there is no resurrection of the dead? 13 But if there be no resurrection of the dead, then is Christ not risen: 14 and if Christ be not risen, then is our preaching vain, and your faith is also vain. 15 Yea, and we are found false witnesses of God; because we have testified of God that he raised up Christ: whom he raised not up, if so be that the dead rise not. 16 For if the dead rise not, then is not Christ raised: 17 and if Christ be not raised, your faith is vain; ye are yet in your sins. 18 Then they also which are fallen asleep in Christ are perished. 19 If in this life only we have hope in Christ, we are of all men most miserable. 20 But now is Christ risen from the dead, and become the firstfruits of them that slept. 21 For since by man came death, by man came also the resurrection of the dead. 22 For as in Adam all die, even so in Christ shall all be made alive. 23 But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming.
Jesus Christ is the resurrection Jn 11:24-25
24 Martha saith unto him, I know that he shall rise again in the resurrection at the last day. 25 Jesus said unto her, I am the resurrection, and the life:
Paul testifies that the OT Fathers believed in the resurrection Acts 24:14-15
14 But this I confess unto thee, that after the way which they call heresy, so worship I the God of my fathers, believing all things which are written in the law and in the prophets: 15 and have hope toward God, which they themselves also allow, that there shall be a resurrection of the dead, both of the just and unjust.
Now the resurrection of the just, or Justified of all time is contingent upon being in Christ ! Its only in Him that all shall be made alive. That goes for King David, or the Philippian Jailor.
Amen Brother, the Church chosen In Union with Christ from everlasting Eph. 1:4 to give His Life for Eph. 5:25, consists of all the Members of His Body the Church Col. 1:18, of both Old and New Covenant Saints; and whom specifically He Justified by His death on their behalf, promising Them / Israel Salvation Is. 45:17; they are one and the same People; and whom at His Second Coming shall He raise them up from the dead. Halleluja!
Glory to God Sister. I also believe the Church of the Firstborn is comprised of Saints from the OT and NT and its the Body of Christ, who is the Firstborn Heb 12:23
to the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
Amen, and indeed Glory to Our God Brother ! These who are the Church of the Firstborn are all those of men and women who die In Christ, and become absent from the body and present with the Lord, such as the thief on the cross when Jesus said, "Today thou shalt be with me in paradise". And also Stephen, who when being stoned called upon God saying, "Lord Jesus receive my spirit".