Being “in Christ” implies believing-Christians being in union with Christ, that is, spiritually residing in the Body of Christ. After all, John 3:18 indicates that unbelievers remain condemned and judged, while Romans 8:1 indicates that those in Christ are redeemed:
John 3:18: “He who believes in Him is not judged; he who does not believe has been judged already, because he has not believed in the name of the only begotten Son of God.”
Romans 8:1-2: “Therefore there is now no condemnation for those who are in Christ Jesus. For the law of the Spirit of life in Christ Jesus has set you free from the law of sin and of death.”
2nd Corinthians 5:17: “Therefore if anyone is in Christ, he is a new creature; the old things passed away; behold, new things have come.”
So, the idea of an “unbeliever who is in Christ” would be virtually unthinkable, requiring the meaning that someone would be both redeemed and simultaneously judged, thus violating the Law of Non-Contradiction.
Ephesians 2:7: “So that in the ages to come He might show the surpassing riches of His grace in kindness toward us in Christ Jesus.”
The Book of Ephesians contains many references to spiritual blessings which are predestined in Christ. In fact, “every spiritual blessing in the heavenly places” is “in Christ.” (Ephesians 1:3) For non-Calvinists, this would make plenty of sense, as things like Redemption, Regeneration and the Indwelling of the Holy Spirit only comes after one is in Christ, being spiritual blessings exclusive to believing Christians in the Church. However, Calvinists teach Pre-Faith Regeneration, which as a spiritual blessing, would then necessitate Pre-Faith placement in Christ. Indeed, that is what Calvinists teach:
What do Calvinists believe?
James White: “When the time comes in God’s sovereign providence to bring to spiritual life each of those for whom Christ died, the Spirit of God will not only effectively accomplish that work of regeneration but that new creature in Christ will, unfailingly, believe in Jesus Christ (‘all that the Father gives Me will come to Me’). Hence, we are not saved ‘without’ faith, but at the same time, Christ’s atonement is not rendered useless and vain without the addition of libertarian free will.”197
So, Calvinists believe in Pre-Faith Regeneration and also Pre-Faith placement in Christ—the latter of which being inconsistent with the Bible:
Romans 16:7: “Greet Andronicus and Junias, my kinsmen and my fellow prisoners, who are outstanding among the apostles, who also were in Christ before me.”
So, we are not “in Christ” before we are born.
Ephesians 1:13: “In Him, you also, after listening to the message of truth, the gospel of your salvation–having also believed, you were sealed in Him with the Holy Spirit of promise.”
We become “sealed in Him” when we hear and believe in the gospel.
197 Debating Calvinism (Sisters, Oregon: Multnomah Publishers, Inc., 2004), 191, emphasis mine