I love this section of Heavenly Flood of Regeneration; it's in Section III:

3d. God's name is the fundamental thing in baptism ; hence who then, with propriety, can deny it to be a saving means, or flood of regeneration ? Ought it to be called a mere emblem ? It is very lamentable, that so many of the different denominations who profess Christianity, make so extremely light of baptism. They are far from believing it to be so valuable a flood of grace, that they, on the contrary, call it a mere emblem or representation of something to be received in some other way ; an outward token, by which Christians are externally distinguished, &c. So we frequently hear it announced from the pulpit, and in a similar form we may read it in some confession books and catechisms. Nevertheless, they all, when they baptise, say in their forms, ' I baptise thee in the name of the Father, and of the Son, and of the Holy Ghost ;' and yet, in the meanwhile, call this baptism, performed in this holy name, a mere emblem ! a representation ! If baptism is a mere shadow, or an emblem, then God's name can be nothing more ; because that is the ground-work of baptism. If so, God himself must be a shadow, or an emblem ; because his name is himself. Thus, if we make baptism an emblem, we must make his name, hence himself, an emblem ! Ought our minds not to recoil at such a grotesque idea ? If God is no more than an emblem, he is no almighty God. Hence what would this be but implied atheism ? Although I do by no means believe that such denominations (who call baptism an emblem) have the least idea that this their doctrine leads to this horrid consequence, else one should think they would surely abandon it. But let them for a moment, without prejudice, cooly reflect on this subject.