I just posted a comment explaining how “faith” does not mean mere intellectual acceptance (except as used by James to condemn a false faith).
I agree that the “faith being reckoned for righteousness” passages are a good place to go looking for answers. But I don’t believe it’s sound to declare that baptism causes our faith to be reckoned as righteousness. Consider such passages as –
(Rom 4:4-5 ESV) 4 Now to the one who works, his wages are not counted as a gift but as his due. 5 And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness,
(Rom 4:23-25 ESV) 23 But the words “it was counted to him” were not written for his sake alone, 24 but for ours also. It will be counted to us who believe in him who raised from the dead Jesus our Lord, 25 who was delivered up for our trespasses and raised for our justification.
(Gal 3:14 ESV) so that in Christ Jesus the blessing of Abraham might come to the Gentiles, so that we might receive the promised Spirit through faith.
You allude to God’s covenant with Abraham — which is exactly right, because it takes us back to first principles. Paul argues both in Romans and Galatians that our salvation is the result of God’s honoring his promise to Abraham — to credit righteousness to those who come to him with faith.
In each case where Paul makes this argument, he states that faith is sufficient (“faith” being, of course, a submissive faith, that is, faithfulness). And that only makes sense, because God didn’t require Abraham to be baptized — only to have faith. How would God be faithful to his covenant with Abraham if he damned those with a genuine, submissive faith because they misunderstood how to be properly baptized?
And notice how Paul argues in Rom 4:10 that circumcision can’t be a requirement of salvation because God didn’t require Abraham to be circumcised until after he was credited with righteousness due to his faith. And yet, much later, God threatened to kill Moses if he didn’t circumcise his children. Ex 4:24 ff. You see, Paul demands that we find our soteriology (theology of salvation) in God’s initial forgiving act with Abraham — with no additions.
So I entirely agree that we need to look at passages such as the Abrahamic-covenant passages — because they show us some of the “why” in the plan of salvation. And hard questions can’t be answered until we dig into the why.
Does that mean we don’t baptize those we convert? Of course, not. And we should speak of baptism as being “into the forgiveness of sins.” We just shouldn’t conclude that God will violate his promise to Abraham just because someone misunderstood the proper way to baptize.