3. The very fact of the church membership of infants in the Old Testament economy is a clear indication of God's will in the regard to this matter. To say that God does not will infants to be members of His visible kingdom is a hard sell, especially considering the fact that Scripture gives us over 2,000 years of it clearly on display in the Old Testament administration of the covenant of grace.
Whatever doubts we may entertain about the status of Old Testament believers, one thing is most definitely clear: the infant children of these believers were in fact members of the church under this administration of the covenant of grace. As such they were the regular subjects of the covenant seal: circumcision.
When God called Abraham and established the covenant with him, not only did he embrace Abraham's infant seed in very clear terms, but He also appointed an ordinance by which this relation of all his children to the visible church was to be publicly ratified and sealed, and this when they were only 8 days old. This covenantal church membership of believers was a self-perpetuating scheme. Every child who was circumcised, that is who received the covenant seal impressed upon their flesh, received it from the hands of adults who had been brought into the covenant themselves when they were but 8 days old. The New Testament explicitly teaches by the inspiration of God Himself, that circumcision was “the seal of the righteousness of faith” (Romans 4:11). Those who view circumcision as being merely a pledge of possession of Canaan and the enjoyment of temporal prosperity in the Promised Land sell the covenant seal short. It was a sign and seal of God’s promise in which “all the families of the earth were to be blessed.”
Let’s step away for a moment and consider how profound the theological implications of the covenant of grace were under the Old Testament administration. One merely has to read Paul’s epistle to the Romans to see this. Paul argues conclusively in that epistle that the covenant of grace exhibited in the New Testament Christian church is exactly the same covenant of grace God established with Abraham. In Galatians, Paul goes so far as to say that if you are in Christ, regardless of your ethnic derivation, you are a child of Abraham according to the promise (Gal. 3:29). And let me hasten to remind the reader that Galatians was not written to ethnic Jews. Calling these Greek Gentiles believers “offspring of Abraham” is a monumentally significant theological statement. It goes to the very heart of how Christians should read the Old Testament. It either applies to us with equal force and relevance as it did to the Jews who lived under that administration of the covenant of grace, or it is utterly irrelevant and useless for Christians. Few, if any, Christians would ever publicly and openly espouse such a radical position. But what difference does that make if, as is typical in evangelicalism, the Old Testament is relegated to realm of legend? Even among those who swear by the plenary inspiration and inerrancy of the Bible, many can be found who absolutely ignore or neglect the Old Testament, which amounts to the same thing as rejecting its relevance.
Now, let’s return to what we were looking at the moment ago. God appointed a covenant seal to ratify this promise and to signify His faithfulness to it. This covenant seal was not appointed by God as some dark, esoteric, mysterious secret initiation rite by which only well-informed adult initiates, after having solemnly received the seal, could be admitted into the covenant relationship. Not on your life. God appointed this covenant sign to be administered, and it actually was administered for nearly 2000 years to infants, only 8 days old, as a sign and token of their relation to God's covenant family and as a sign of their right to the privileges of that covenant. Now we ask the burning question: If God in His infinite wisdom saw that it was right that infants should be made the subjects of the “seal of the righteousness of faith” before they were capable of exercising faith, why should a transaction the same in substance, not be right and suitable now?