We receive Christ's saving work in baptism when we come to hime with faith.
"He who believes
and is baptized will be saved" (Mk 16:16)
Faith + Baptism = Salvation.
We are sealed with the Holy Spirit in baptism
.
"For as many of you as were baptized into Christ have put on Christ. (Gal 3:27).
"
But it is God who establishes us with you in Christ, and has commissioned us; he has put his seal upon us and given us his Spirit in our hearts as a guarantee." (
2Cor 121-:22)
When we are clothed with Christ we have been put into Christ and God gives us the Holy Spirit in our hearts. Just as was prophesied by Ezekial (
Ez 36:25-27):
Yes, Paul's primary mission was to preach. He could leave others who travelled with him to perform the baptisms.
But Paul was interested in baptism.
He detected a problem with the 12 men at Ephesus (Acts 19) and asked how they had been baptised. When he found they had only been baptised in John's baptism he immediately had them baptised "in the name of the Lord Jesus" - baptised into Christ.
Or are you unaware that we who were baptised into Christ Jesus were baptised into his death? We were indeed buried with him through baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, we too might live in newness of life. For if we have grown into union with him through a death like his, we shall also be united with him in the resurrection.
(Rom 6:3-4)
“..he saved us, not because of any works of righteousness that we had done, but according to his mercy, by the washing of regeneration and renewal in the Holy Spirit.” (Titus 3:5)
But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God. (1Cor 6:11)
You were buried with him in baptism, in which you were also raised with him through faith in the power of God, who raised him from the dead. And even when you were dead (in) transgressions and the uncircumcision of your flesh, he brought you to life along with him, having forgiven us all our transgressions; (Col 2:11-13)
"For as many of you as were baptized into Christ have put on Christ. (Gal 3:27).
"
But it is God who establishes us with you in Christ, and has commissioned us; he has put his seal upon us and given us his Spirit in our hearts as a guarantee." (
2Cor 121-:22)