There are so many promises in the N.T. made to those who are “in Christ” but, that idea may be a little obscure. We know that Christ enters us when we are born again and He “will never leave us or forsake us but, what does it mean to be “In Christ?”
The truth is that we are a 3 part being, just as God is. We were made in His image and He is 3 in 1. We also have a spirit, soul and body.
Before we are born again, our spirit man (innermost being) is dead in sin. Jesus gives us a new spirit that is joined to His Holy Spirit! (1 Cor.6:17) This is being born-again. However, our soul and body are not immediately made new.
We are promised that our body will be made new when Jesus restores all things but, our soul is our responsibility. We must work out the salvation of our soul in fear and trembling(Phil.2:12). We must hold firm to the Gospel, which is able to save our souls (1 Cor.15:1,2 & James 1:21). There are exhortations in almost every single N.T. book for us to endure to the end to save our soul and similar sayings and I would gladly share the list that I have compiled over the last 18 months.
We must abide in Jesus, the Word and stay in the Holy Spirit to be “in Christ”. Being born-again is a once and done deal (spirit). The promise of salvation for our bodies is future and the salvation of our souls is the process of sanctification in this life. Sanctification ends at death. We never “arrive” to complete salvation until we are done “running the race”.
I believe it is true that not every born-again believer is “in Christ”. “In Christ” is an existence, a process. It is not an event. The event is the new birth but abiding is the process, which is why Jesus kept reminding His faithful 11 disciples to abide in Him. in John 14-17
This is why promises are made to those “in Christ”. Because, many promises in the N.T. are not simply made to born-again believers who have Christ in them but to the faithful follower of Christ, who is following the Spirit!
Rom. 8:1- “There is therefore now no condemnation for those who are in Christ Jesus.“
Rom.8:13-“but if by the Spirit you put to death the deeds of the body, you will live.”
Eph.1:3b- “who has blessed us in Christ with every spiritual blessing in the heavenly places”
I just noticed that Ephesians 1 uses the phrase “in Christ” 10 times or more! Our spirit is now and will continue to be “in Christ” but, we get “out of Christ” whenever become unlike Christ.
I believe it really is as simple as recognizing when we are not manifesting fruit of the Spirit. If our attitude is contrary to the fruit of the Spirit, we (our soul/body) is no longer “in Christ.” We are still born-again. Our Spirit is still joined with His Spirit but, the rest of our being can get “out of Christ” and also out of the promises.
1 John 3:23,24 say “This is His commandment, that we believe in the name of His Son Jesus Christ, and love one another, just as He commanded us. The one who keeps His commandments abides in Him, and He in him. We know by this that He abides in us, by the Spirit whom He has given us.”
The one who loves as Jesus commanded abides in Him. This is how we know that He abides in us!