What is a sign? What is a seal?
The sign is the "pointer" to something else.
The seal is the "signet mark" of God's ownership.
Under the Old Covenant, circumcision served as the external mark of God's internal, spiritual mark. That mark, the real mark, could only serve its purpose when faith appropriated it.
The same is no less true of the New Covenant sign, baptism.
The efficacy of baptism is not tied to that moment of time wherein it is adminstered; yet, notwithstanding, by the right use of this ordinance {by faith}, the grace promised is not only offered, but really exhibited, and conferred by the Holy Ghost, to such (whether of age or infants) as that grace belongeth unto, according to the counsel of God's own will, in his appointed time. WCF 28.6
When does God mark somebody as his spiritual property? The baptist says that he only does so when the person exercises faith the first time. The presbyterian says no. It happens in conjunction with baptism--not by the operation of sacramentalism--and not in violation of the principle that "grace and salvation are not so inseperable annexed unto it, as that no person can be regenerated, or saved without it; or, that all who are baptized are undoubtedly regenerated" (WCF 28.5).
God declares ownership of the children of true believers, in a way he does not do with the children of the unsaved. Why? 'Cause he wants to. When does he do this? At their birth. Signifying and sealing the Covenant of Grace, the mark (be it circumcision or baptism) even declares their
election ("promising to give unto all those that are
ordained unto eternal life his Holy Spirit" WCF 7.3), though not infallibly (just as adult baptism
also does not declare the same thing, infallibly). How fit, then, that such should be placed on designated persons as soon as humanly possible.
The newness of the new covenant consists in no small part of its sheer scope. The Spirit of God is "poured out on all flesh." Thousands, millions swept into the kingdom of grace. The borders of Israel, the tents of Shem are too small. "Lengthen the cords." Hebrews 8:8 "Finding fault with
them...." With what? the covenants? the administration? No, with them, the people of the Old Covenant. Even then, with all the externals, all the means of grace, all the blessings given by God,
sin still ruled. Wickedness reigned in their hearts. Idolatry, idolatry, idolatry. Nothing was too immoral or too dispicable.
The grace of regeneration dripped out like an eyedropper. The grace of parental faithfulness was restricted. Haven't you ever wondered how it was that over and over and over children did not adopt their parent's faith? Start in Judges. The next generation, chapter 2 verse 10! Eli's sons. Samuel's sons. David's sons! Where do we find intergenerational faithfulness? It is the
exception, and not the rule! What makes the New Covenant new? The phrase "I will be a God to you, and to your children after you," has seen fulfillment since Pentecost! No, not every child. Not every generation the same. The ebb and flow of saving grace is still a reality.
But the tide is coming in.
[Edited on 11-15-2005 by Contra_Mundum]