Uh oh! This sounds like salvation through Christ + works. Didn't you learn from Paul's lesson to the Galatians?
To believe this, one has to believe that this man had been circumcised, something that there is no proof for in scripture (perhaps he was stealing because he was poor, and his parents before him were poor, and as a result they couldn't afford to pay for his circumcision?) So if you believe that circumcision contributed to the man's salvation, you might as well believe that baptism contributed to his salvation, as scripture is silent on both matters. Both are Christ + works false gospels, so both are equally dangerous.
In the OT dispensation, God stated that being in covenant with Him required one to be circumcised. I didn't say that, God did. God also said that the uncircumcised person would be cut off from his people for breaking covenant with God.
"This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.
And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.
And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed.
He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.
And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant." Gen 17:10-14
Also, Moses son had not been circumcised which prompted the Lord to set out to kill him:
Ex 4:24-26
And it came to pass by the way in the inn, that the
Lord met him, and sought to kill him.
Then Zipporah took a sharp stone, and cut off the foreskin of her son, and cast it at his feet, and said, Surely a bloody husband art thou to me.
So he let him go: then she said, A bloody husband thou art, because of the circumcision.