The law of circumcision

Having grown up understanding the teaching on infant baptism and the necessity of accountability in judgement it is easy to forget that the early law given to Abraham included the law of circumcision in which those boys who were not circumcised were not children of the covenant. It is not exactly the same as the concept of infant baptism because the penalty was a loss of blessings rather than a supposed eternal damnation but it certainly explains how people could conclude that the lack of an outward ordinance could cut someone off of the path to salvation.