I never thought that I’d be leaning on the Reformers for evidence, but I ran across this interesting article:
http://www.prca.org/articles/infant_baptism.html
The argument of the Form for the Administration of Baptism is founded on the truth that infants can be and are saved by God (Ps. 139:13, Jer. 1:5, Lk. 1:15, Mk. 10:13-16). If they can be saved, they can also receive baptism as the sign of salvation. To say that they cannot have the sign when they can have the salvation to which the sign points is inconsistent, to say the least.
A baptist will argue, however, that a person must give evidence of having salvation before he can receive the sign. He will insist, therefore, that faith must precede water baptism. So, he says, water baptism ought to be administered only to believers. The bedrock of baptist teaching is, then, the idea that faith must precede water baptism.
This teaching is based on a misinterpretation of Mark 16:15, 16. These verses, however, do not say that faith must precede baptism. Nor does any other Scripture passage. The argument that this is the order of the passage is really no argument at all. It is true that faith is mentioned before baptism in Mark 16:15, 16. That order is important. But that does not prove that the order is a temporal order, i.e., first faith, then baptism. The passage does not say, ‘He that believeth and then is baptized shall be saved.’ Baptists assume that it says ‘then’ but it does not. The order in Mark 16:15, 16, is simply that of priority, i.e., that faith is more important than baptism, something we all believe.
Following the Baptist line of reasoning, one might just as easily prove from II Peter 1:10 that calling comes before election, because it is mentioned first. In fact, following the Baptist line of reasoning, the order in Mark 16:15, 16, is first faith, then water baptism, then salvation; an order no baptist could accept. All Mark 16:15, 16, proves, then, is that faith, baptism and salvation are very closely related to each other.
The main point of the Form for the Administration of Baptism, however, is that infants are saved ‘without their knowledge’. In this way the Form connects infant baptism and sovereign grace.
That infants are saved without their knowledge is self-evident. But this means that there is no other way to save an infant than by sovereign grace. He cannot respond to the Gospel, exercise saving faith, make any decision, or do any works, and must, then, be saved solely by the sovereign grace of God. Infant salvation, therefore, is a powerful demonstration of salvation by grace alone.
What is more, the salvation of infants demonstrates what is true for everyone whom God saves. We must all become like little children if we are to enter the kingdom of heaven, that is, we must be saved in the same way that a little child is saved, without our having done anything in order to be saved.
Many baptists believe this. Holding to the doctrines of grace and believing the sovereignty of God in salvation, they insist as we do, that God is always first in the work of salvation. Faith, therefore, is not something that precedes salvation, but is itself part of the gift of salvation (Eph. 2:8-10). It is not something we produce in order to be saved, but something God gives us in saving us.
Yet, the same baptists who insist that faith cannot not precede salvation, say that it must precede the sign of salvation. How inconsistent! Ought not the sign correspond to the reality? If it is not necessary to have faith before God can begin to save us, then the sign ought to say so. In infant baptism it does!
http://www.prca.org/articles/infant_baptism.html
It is true that Reformed Baptists have a friendly disagreement with the rest of Reformers about infant baptism. However, in no case does any Reformer believe that water baptism has anything to do with salvation itself. The article affirms that salvation is by grace alone. That is the meat of the matter.