Gavin Ortlund wrote an article titled, Why I Changed My Mind About Baptism. In this article, the argument he presents is poor, weak, and twisted, revealing a lack of knowledge and understanding not only of baptism, but also of circumcision. In his article, he writes: "The faith of an Israelite child's parents was not what determined the child's right to circumcision; it was the child's association with the nation of Israel." While this is not entirely accurate or correct, the same argument can be applied to baptism and the church. So once again, it supports infant baptism because a child's association with the church is that they are full members thereof.
When you were born, were you born as a full citizen of your country with all the rights and responsibilities thereof? Yes, you were. However, because you were young, you did not know of these rights and responsibilities and could not appropriate them. You had to be taught them. When you were older, you then either embraced them as your own or rejected them, which is treason and demands you leave your country. The same is true concerning circumcision and baptism. The son circumcised on the 8th day had no faith of his own. He knew nothing of the covenant promises and had to be taught it. As he grew, he could then embrace what he was taught by faith and appropriate the blessings unto himself, or reject what he was taught and appropriate the curses unto himself. The same is also true of baptism, which people would see and understand if they practiced it in accordance with what we see in the Scriptures.
Gavin goes on to ask this ridiculous question: "So, given paedobaptist presuppositions, why not baptize the grandchildren of believers, too? If we're really building off continuity with the Old Testament precedent, why stop at one generation?" The ridiculousness of this question can be seen in a number of ways. First, infant baptism does not stop at one generation. Where Gavin gets this foolish concept from I have no idea. There are families who, by God's grace, have a legacy of faith from generation to generation to generation, just as promised in Scripture. Each of these generations has faithfully baptized their children. The precedent of the Old Testament did not circumcise grandchildren, so where does Gavin draw this foolishness from?
Second, for a man who grew up in and around Presbyterians, Gavin has completely missed the mark on this issue. This may not entirely be his fault, but the fault of the churches he attended. As Bryan Chapell writes, "We must confess that some bring their children for this sacrament because of the sweetness of the ceremony, or because of the traditions of family and church, or even with the misguided expectation that somehow 'holy water' will magically protect their child from hell. Yet neither sentiment nor tradition nor superstition is sufficient reason for believers to bring their children to be baptized. ... We baptize infants because we believe that the Bible teaches us to do so."
Third, apparently Gavin is unaware that God does not have any grandchildren.
Gavin continues by making a fallacious argument. He writes, "Those who espouse infant baptism bear responsibility to define the word infant. ... But it's difficult to see how that would be consistent with Genesis 17 or the practice of God's people throughout the Old Testament." Paedobaptists bear no such responsibility. The command is clear from Scripture. Apparently Gavin does not understand Genesis 17 or the practice of God's people through the Old Testament. Once again, never were grandchildren circumcised. The children were always circumcised by their respective parents. Do you think Ishmael and Esau did not circumcise their children? They have nothing to do with Israel, but they have much to do with Abraham. Circumcision was always connected to the faith of the parents, regardless of the genuineness of that faith. If you have parents in the Presbyterian church whose faith is not genuine, and they baptize their infants, do you think that somehow changes anything? Gavin's mentality on this issue seems to be entwined in the misguided belief that baptizing your children somehow protects them from hell or ensures they will be Christians. For all his "intensive study," he does not seem to have learned a thing.
Gavin continues further by making a false statement: "In no biblical covenant or redemptive-historical era has the sacrament of initiation been for 'those who believe and their children.'" History disagrees with him, as does Reformed tradition.
Gavin ends his article by asking a bunch of ridiculous questions centered on his foolish concept regarding grandchildren. Where he pulled this theory from is beyond me, but it is clear that he is desperately reaching in his attempt to argue against something he has clearly failed to grasp through his "intensive study." The fact of this can be seen in his statement: "Better, and more continuous with circumcision and the OT precedent, I think, to define the church simply as the children of Abraham: defined by physical descent throughout the OT (Gen. 17:9), and defined by spiritual descent throughout the NT (Gal. 3:7)." Many Muslims are physical descendants of Abraham, yet they are not the church. It appears as though Gavin's confusion runs greater than simply baptism and circumcision, as he does not seem to understand who and what the church is either. In the Gospel of John, Jesus identifies the Jews as descendants of Abraham (8:37), but tells them they are not his children (8:39) but the children of their father, the devil (8:44). Being physically descended from Abraham did not mean you were part of the church. It has always been the spiritual descendants of Abraham in both the Old Testament and the New Testament who were part of the church.
Gavin, you need to conduct a lot more study. Your conclusion in your article is drawn from assumptions, as well as a lack of understanding concerning these elements. I would call it a blundering conclusion as the evidence from your article reveals a lack of knowledge and understanding of not only baptism and circumcision and everything surrounding them, but also of the church. In case you missed it, Paul refers to our baptism as circumcision (Col. 2:11-12). Both of these are in the metaphorical use, expressing a change of identity having taken place, which is what both circumcision and baptism infer, but may not be the reality. How many people in the OT were circumcised and yet no change ever took place in their life? How many people in the NT were baptized and yet no change ever took place? Judas? Simon Magus? Demas? See Baptism's Meaning.
See also Michael Horton's Infant Baptism: God's Grandchildren.