I remember you asking this in the other thread. I did respond to it. You probably just missed it or whatever. I will re-post what I had said over there onto here. Here is the link to the page and post:
http://christianchat.com/bible-discussion-forum/147723-when-did-church-begin-4.html
Isaiah 45.25
In the LORD shall all the seed of
Israel be justified, and shall glory.
Being in Christ is not exclusive to only Paul's mystery and the body of Christ. People saved back in Acts 2 were also
in Christ. My points above still stand. And you are bypassing the elephant in the room. Which is that Paul states the body of Christ was a mystery. Since that is true, the people in Acts 2 cannot be when the body of Christ starts. They are part of the Little Flock, the believing remnant, who were looking for a kingdom on Earth.
Also, take note that Romans 16.7 says that they were his
kinsmen. Who was Paul? He was a Jew. So him saying that these two were Jews gives even more evidence,
but certainly not the only evidence, that they were saved under Peter's gospel. They were not members of the body of Christ.
I'll give an excerpt that goes in to better detail below from Justin Johnson if your interested.
Skeptics of the special revelation given to Paul are quick to point out that there were people “in Christ” before Paul. Out of the 78 times in the Bible the phrase “in Christ” shows up, Paul uses the phrase 75 times. It is clear that the phrase is distinctively Pauline.
Afterall, to Paul was revealed the mystery of God’s will that…
“in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him” – Ephesians 1:10
The all things
in Christ consist of the prophesied earthly things, but also the heavenly things revealed as the mystery of Christ kept secret since the world began.
It is evident that God’s purpose has always been for all things to be
in Christ.
So, when Paul describes Junia and Andronicus as being “in Christ before me”, this is seen as an admission that those before Paul taught the same thing as him. Yet, this would be an hasty conclusion since merely being
in Christ is not the mystery of Christ kept secret since the world began (
Rom 16:25). Both the prophets and the Lord in his ministry to Israel talked about being
in him.
We can read in the prophets that Israel would be justified in the Lord:
“In the LORD shall all the seed of Israel be justified, and shall glory. “ – Isa 45:25
Throughout the prophetic writings finding refuge
in the Lord was a common theme. Being glad, rejoicing, and resting
in the Lord were common admonitions.
That salvation was found
in the Lord, and subsequently in the Lord Jesus Christ was no mystery.
Peter and the twelve, along with Adronicus and Junia, had to be
in Christ according to God’s earthly prophetic purpose.
The phrase “In him”, found at the end of
Ephesians 1:10, is the phrase used more often by John in his writings about being in Christ.
“ And he that keepeth his commandments dwelleth in him, and he in him.” – 1 John 3:24
Jesus taught his disciples to abide in him (
John 15:4) as the true vine. If they did not abide, by keeping his commandments, they were
cut off and cast forth.
Fortunately, your position in Christ
is not that of a branch but a body
member (
Eph 5:30).
God does not cut off body parts. You and I are in Christ according to the revelation of the mystery of Christ. Our position in Christ is without the commandments of the law, and is apart from Israel’s covenants.
Being in Christ was always part of God’s plan for heaven and earth. That Israel needed to be found in the Lord was nothing new. When Christ came, he taught they needed to be in Him, and that they would be one with the Father (
John 17:21). Those in Christ according to prophecy were part of Israel’s kingdom covenants (
John 15:5).
Those that are in Christ according to the mystery dispensation of Christ are part of a new creature, without Jew or Gentile (
2 Cor 5:17,
Col 3:10-11). Out of two, Jew and Gentile, God made one new man in Christ in this dispensation (
Eph 2:15-16).
The difference between prophecy and mystery is not that one would be in Christ and the other would not. The dispensational difference is
how we come to be in Christ. This has always been the difference.
The mystery of Christ explains how ungodly Gentiles could be in Christ without the law and access to the covenants. This mystery was not known by any of the prophets in time past until the Lord chose to reveal it to the apostle Paul.
Link references and video
In Christ Before Paul
Romans 16:3-16