If NT baptism is a fulfillment of OT circumcision (notice I said "if") then go to
Romans 3 and 4 and substitute "baptism" for "circumcision"
27Where is boasting then? It is excluded. By what law? of works? Nay: but by the law of faith.
28Therefore we conclude that a man is justified by faith without the deeds of the law.
29Is he the God of the Jews only? is he not also of the Gentiles? Yes, of the Gentiles also:
30Seeing it is one God, which shall justify the baptized by faith, and unbaptized through faith.
31Do we then make void the law through faith? God forbid: yea, we establish the law.
Romans 4
1What shall we say then that Abraham our father, as pertaining to the flesh, hath found?
2For if Abraham were justified by works, he hath whereof to glory; but not before God.
3For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.
4Now to him that worketh is the reward not reckoned of grace, but of debt.
5But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
6Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
7Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
8Blessed is the man to whom the Lord will not impute sin.
9Cometh this blessedness then upon the baptized only, or upon the unbaptized also? for we say that faith was reckoned to Abraham for righteousness.
10How was it then reckoned? when he was in baptism, or in unbaptism? Not in baptism, but in baptism.
11And he received the sign of baptism, a seal of the righteousness of the faith which he had yet being unbaptized: that he might be the father of all them that believe, though they be not baptized; that righteousness might be imputed unto them also:
12And the father of baptism to them who are not of the baptism only, but who also walk in the steps of that faith of our father Abraham, which he had being yet unbapgtized.
13For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.
14For if they which are of the law be heirs, faith is made void, and the promise made of none effect:
15Because the law worketh wrath: for where no law is, there is no transgression.
16Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,
17(As it is written, I have made thee a father of many nations,) before him whom he believed, even God, who quickeneth the dead, and calleth those things which be not as though they were.
18Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken, So shall thy seed be.
19And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sarah's womb:
20He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God;
21And being fully persuaded that, what he had promised, he was able also to perform.
22And therefore it was imputed to him for righteousness.
23Now it was not written for his sake alone, that it was imputed to him;
24But for us also, to whom it shall be imputed, if we believe on him that raised up Jesus our Lord from the dead;
25Who was delivered for our offences, and was raised again for our justification.