God’s purpose is accomplished by the gospel, it is to offer everyone who was ever born in the world another birth, the born-again experience (spiritual) to become a member of His family. This is done, by the Holy Spirit.

The main Scripture that teaches this is Eph 1:12-14: “that we who first trusted in Christ should be to the praise of His glory. In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, who is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.”

Eph.1:13. “In Him” YOU also trusted- The gentiles are included with the Jews. After you heard the word of truth - the GOSPEL of our salvation, what you believe in is whom you believe in; a person and what that person did on the cross.

Notice that is after you heard the truth, not before, that you are sealed. It is an unseen work that one receives after they trust the Gospel by believing, they are then sealed with the Holy Spirit.

“In whom also,” en hoo, through whom, Christ Jesus. After you had believed, the blood redemption is applied, you were sealed with the Holy Spirit of promise; that is the Holy Spirit whom is promised to all those who believe on Christ Jesus, He is freely given to you. He freely has given us all these things, although some things we still have to wait for.

Paul says a similar thing in a different way to the Thessalonians. 2 Thess. 2:13-14 “But we are bound to give thanks to God always for you, brethren beloved by the Lord, because God from the beginning chose you for salvation through sanctification by the Spirit and belief in the truth, to which He called you by our gospel, for the obtaining of the glory of our Lord Jesus Christ.”

As believers in the New Covenant we are cleansed by the blood and sealed by the Holy Spirit as proof that what took place was our believing the gospel.

The gift of eternal life begins for the believer with the Holy Spirit indwelling him (Romans 8:8-11). 2 Cor.1:22 (God) who has sealed us, and given the earnest of the Spirit in our hearts.”

The Spirit is holy and he makes us holy. He is called the Spirit of truth and promise and by him believers are sealed; that is, separated and set apart for God, distinguished and marked as belonging to him. He is instrument of sanctification and of the new birth (John 17:17; 2 Tim. 2:15; James 1:18).

The `sealing' [aorist tense] is spoken of as past, once for all. It is not a continual event; the Spirit's present testimony is there working in us to know we are in him and being taught the truth.

Sealing- Gr.Aurobon- a down payment like wedding ring- assuring we are engaged. In Biblical times a seal was attached to a letter or legal document to authenticate who its from or ownership. The seal of God, is the Spirit who descends upon us as an individual and takes residence inside and confirms us as God’s children. This is the baptism of the Holy Spirit 1 Cor.12:13, it is being born again (Jn.3:3). Our adoption occurs through the Spirit at regeneration (Rom. 8:15-16), (afterwards subsequent fillings). The gift is the Holy Spirit resident with all his influences, gifts and talents that accompany Him.

He is said to be our companion for the redemption of the purchased possession. Rom.8:23 “Not only that, but we also who have the firstfruits of the Spirit, even we ourselves groan within ourselves, eagerly waiting for the adoption, the redemption of our body.” We have been adopted but we are waiting for the promise to be complete, which is our inheritance.

God does not break his promises, we are engaged to be married; we as the church are to be the Bride of Christ (the bride is collective not individual). The Father drew us to the Son. If we accept we are in an unconditional covenant relationship, meaning it is not dependent on us but on Him. We cooperate in submission as a wife to her husband or a child to his parents. By doing this we stay in his grace and grow.

We become adopted by regeneration. The New Testament word for adoption means to place as an adult son. Sonship is automatic but our growth is not. We get out what effort we put in it. Not that it is based on us but by our cooperation, by submission and yielding to the guidance and leadership of the Holy Spirit that now lives in us. His grace flows abundantly to those who are adopted children.

Eph. 4:30: “And grieve not the Holy Spirit of God, whereby ye are sealed unto the day of redemption.”

This “sealing” is the down payment, of the rest of the redemption we will receive when we have the bodily change described in1 Cor. 15:51-58. “Earnest” is defined by Strong’s as a signet (as fencing in or protecting from misappropriation); by impl. The stamp impressed (as a mark of privacy, or genuineness), lit. or fig: seal.

This takes on the form of instruction which leads the new believer away from sin and unrighteousness into righteousness. The sanctifying work that leads us in the right direction and away from the wrong one. It is a “child training” experience, and can include discipline if necessary (Heb. 12:6,7).

This Spirit of truth the world rejects is with the believer separates us from the world and its ways John 14:17. John 14:26 leads us into all truth, 1 Jn.2:27. He teaches all things, John 16:13-14: “However, when He, the Spirit of truth, has come, He will guide you into all truth” “He will glorify Me, for He will take of what is Mine and declare it to you.”

I become a son (child) of God by faith in Jesus Christ, my response is that I serve Him, “As many as are led by the Spirit are the sons of God.” (Romans 8:14).

Having been born from above, we are urged by Peter as newborn babes, to desire the sincere milk of the word that ye may grow thereby” (1 Pet 2:2). He has already said they were begotten again unto a living hope (1:3) and now urges us to develop (grow) as God's children.

The apostle John in 1 John he cites 3 degrees of progress “little children”, “young men”, “fathers” (1 John 2). We are to grow as in real live from a babe to an adult. Become mature in the faith.

He set his seal of ownership on us by putting his spirit in our hearts as a deposit guaranteeing what is to come. There are no refunds on his deposit.

Rom.8:9; “If anyone does not have the spirit of Christ he does not belong to him.”

1Cor. 3:16: “do you not know that you are the temple of God and that the Spirit of God dwells in you.” The spirit is his assurance to us we are owned by him and He is working in us to give God glory.