I have great respect and affection for Paedobaptist Christians who argue along these lines. Some of them are my close friends or historical heroes. And the arguments [for paedobaptism] I’ve sketched above display careful attention to Scripture and reverence of Scripture. Yet I don’t think they’re persuasive. Here are six reasons why.

1. Paedobaptism applies the sign of union with Christ to those who are not united to Christ. It divorces the sign from the reality.
2. Paedobaptism confuses being born of Christian parents with being born again by the Spirit.
3. Paedobaptism mistakenly assumes that God is forming his new covenant people the same way he formed his old covenant people.
4. Paedobaptism undermines the church’s saltiness and lightness (Matt. 5:13-16).
5. Paedobaptism dissolves two crucial differences between baptism and circumcision.
6. Paedobaptism makes God’s new covenant promise less than a promise.

Bobby Jamieson, Understanding Baptism (pg. 25-35).