I understand the fact that after the rapture the Holy Spirit will no longer be sealed within those who become believers. It is however too difficult for me to share this with my brothers and sisters in Christ because they continue to look at the New Testament scriptures for the Church and believe God would not give the sealing of the Holy Spirit to one believer and not another, even if it is a Tribulation saint.
The Bible makes it pretty clear that the age of Grace didn’t put an end to the age of Law but instead interrupted it seven years short of its promised fulfillment. This seven years will be fulfilled after the rapture (Daniel 9:24-27, Romans 11:25-26, Acts 15:13-18). But this idea is hardly ever taught as such in the Church. Because of the tremendous influence of replacement theology (the opinion that Israel was replaced by the church following their rejection of the Messiah) on the Church, even sound evangelical teaching rarely mentions it. Instead, We refer to the seven years as the Tribulation period instead of its proper name, the 70th Week of Daniel. Therefore, most people have been taught that the New Covenant replaced the Old Covenant at the cross and after that everyone receives the seal of the Holy Spirit.
They don’t realize that the New Covenant as we know it ends with the rapture, and after that sacrifices for sin and obedience to the Law will be required again for Israel, along with faith in the Messiah. This will also be the case for Israel during the Millennium (Ezekiel 40-47) even after they receive the New Covenant. For Gentiles in the Millennium it appears that obeying the commandments and holding on to their faith in Jesus will be required along with an annual visit to Israel for the Feast of Tabernacles (Rev. 14:12, Zechariah 14:16-19).
Also, Gentile Christians tend to focus on the Church and not on Israel. You’d be surprised at the number of questions I get about Israel’s return to animal sacrifice and the need for a Temple during Daniel’s 70th week and where Israel will be during the Millennium. These questions are all due to the fact that most people have never been taught about the Millennium from Israel’s perspective. Therefore you shouldn’t be surprised if your friends are not aware of this.
The bottom line is that the Church has a totally unique relationship with the Lord. No group before or after the Church will enjoy such intimacy with Him. Paul said this is so that in the ages yet to come God could demonstrate the incomparable riches of His grace expressed in His kindness to us in Christ Jesus (Ephes. 2:7).