In his discussion of the Nicene creed’s statement “one baptism for the remission of sins,” T. F. Torrance explains what it means to be baptized into Christ:
“In baptism we are united to Christ through the Holy Spirit in such a way that we partake of the whole substance of the gospel, for all grace and truth are embodied in him. We may recall the point made by Irenaeus in this connection, when he claimed that the incarnate Son is called and actually is, ‘Salvation, Savior, and Saving Activity‘ and that thus he is ‘salvation made flesh.’ In other words saving grace is not something detached from Christ which can be dispensed at will, but is identical with Christ in the unity of his Person, Word, and Act. It is through the one baptism which we have in common with Christ, or rather which he has in common with us, that we share in all that God has in store for us. Because baptism is one (the baptism with which Christ was baptised for our sakes, and the baptism in which we are given to share in all that he was, is, and will be) to be baptised is much more than to be initiated into the sphere where forgiveness is proclaimed and dispensed in the Church. It is to to be ‘delivered out of the power of darkness and translated into the kingdom of God’s dear Son in whom we have redemption through his blood, even the forgiveness of sins.’ It is to have our frail, transient existence taken up into Christ himself in such a way, that without any loss to our creaturely reality but rather with its perfecting through his Spirit, it is united to God and established in union with his eternal reality.” (The Trinitarian Faith, p. 297)
So. Jesus is Salvation made flesh [all life is in Him and apart from Him there is no salvation; grace and forgiveness are found in Him alone]. The Spirit unites us to Jesus through baptism, uniting us with His body, the Church, which is the kingdom, house and family of God, the community of faith, the assembly of the saints, outside of which there is no ordinary possibility of salvation. So when Peter says, “baptism now saves us” he is saying “Jesus saves us.” By baptism the Spirit of Jesus unites us to the Church. The Church is the body of Christ Jesus. Christ Jesus is Salvation made flesh.