Over at The Daily Genevan, Shane Anderson wrote a good article on baptism meaning the same to adults and infants. I added to Shane's point by stressing Calvin's position that baptism withheld is truly grace withheld. This whole idea has been of particular importance to me because of my conversion from baptistic ideology.

This emphasis has also stuck with me because they belonged to John Murray. Murray was cruical in my fully accepting the Reformed view on baptism. I have previously expanded on particular quotes from Murray but would like to do so again here,

"If it is proper to administer baptism to infants, then the import of baptism must be the same for infants as for adults. You cannot have one meaning for infants and another for adults. Baptism is the sign and seal of membership in Christ body, the church. Baptism must be for them, no less than four adults, the sign in seal of union with Christ in the virtue of his death in the power of his resurrection." (45)

Any attempt to make infant baptism different from adult baptism works against the Reformed position. Karl Barth was critical of John Calvin in this way and I'm inclined to agree that Calvin's enumeration in the Institutes was not ideal. Murray speaks clearly that baptism for infants and adult is precisely the same in substance and potency. Against this backdrop, Murray explains that we must deal with those who receive holy baptism yet fall away. He begins by discussing a number of incorrect ways to explain or reason how recipients of baptism still fall away, 

"What is being contended for is that baptism may never properly be said to be the sign in seal of the external relationship rather than of the covenant itself in its richest and deepest blessing. There is not the slightest warrant from scripture for the notion that baptism or, for that matter, circumcision is simply the sign and seal of external privilege." (52)

I highlight this one because there is a common approach in reformed circles to leave the value of baptism to mere "external privilege." Murray argues against this idea that baptism brings only some set of external blessings detached from the internal promises of the sacrament. Once our thinking starts down that path nothing but memorial thinking remains.