Jesus accomplished our salvation historically, two millennia ago. We cannot go back in time to when that happened. We cannot go to the cross. It’s a historical and temporal impossibility. So what does God do? He brings that historically-accomplished salvation to us, he brings the cross and empty tomb to us. How? Through various means or channels. He uses the preaching of the Word as a channel. Through the Word, preached now, God delivers to us what Jesus accomplished then. He also puts that Word in the water of baptism, so that it is no longer simple H2O, but simple water wed to the strong Word of God. Through the Word-saturated-water, our Father baptizes us into Jesus, joins us to his life, death, and resurrection. As Paul says, “Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death? We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life” (Rom. 6:3-4).
We don’t baptize ourselves; God is always the baptizer. Sure, he uses human hands, but those human hands are just divine tools that our Lord uses. So baptism is not something we do for God, but something that God does for us. Through the means or channel of that Word-Water, the Lord joins us to Jesus, thereby saving us, giving us now the salvation that Jesus accomplished long ago. As Peter wrote, “Baptism…now saves you” (1 Peter 3:21). It is not merely a symbolic act that we do to show God how committed we are to him; it is a divine action where God shows us how committed he is to us.
Regarding whether someone can be saved apart from baptism:
As the older theologians put it, "It is not the absence of baptism that condemns, but the despising of it." Baptism is the *ordinary* means by which the Lord brings us into his kingdom, but if someone believes by hearing the Word of the Gospel, but is unable to be baptized (whatever the reason might be), the faith they have receives the full, forgiving Christ.
Written by Chad Bird, 1517 Scholar