Fred Malone answers the question (this comes from his review of the book The Case For Covenantal Infant Baptism):
15. “In Jesus’ Name, Amen”
R.C. Sproul, Jr. ties the issue of infant baptism to family worship. He says that baptism increases the odds that our children will be saved (306). It gives them the right to pray in Jesus’ name, something unbaptized children cannot do since it is assumed that they are not saved. Baptism is a sign of faith. As far as we know, baptized children are in the faith, the church, the kingdom, and the covenant. Family worship brings them before the King as their King with a right to approach Him in prayer. Even though infant or household baptism is not an ironclad guarantee of salvation, we should assume that they are in the faith till they prove otherwise and are excommunicated as apostates. This is how God worked in His OT covenant arrangements and we should assume that He is the same today (307–309). The primary question is: how do we see our covenant children? If we see them as unsaved, then family worship will take on the character of evangelism; we must warn them of wrath and the need of repentance. However, if we see our children as young servants and recipients of grace, we come before God in family worship as a whole family. Our children will think of God as a loving Father rather than an angry judge. So, the goal of family worship becomes sanctification, not conversion. We must still preach the gospel and pray with them. Family worship makes us think more clearly about the issue of infant baptism (310).
Contra 15. Family worship is certainly an issue in all our homes, whether Baptist or paedobaptist. Some paedobaptists have caricatured the Baptist position, claiming that Baptists can only evangelize their unbaptized children as children of Satan, never teaching them to pray and depend upon God as a believer. Yet, on what basis did Noah and Job teach their uncircumcised children to worship God? On the contrary, family worship becomes the opportunity to call our children to pray to God as His creatures (who are totally dependent on Him for food, shelter, and salvation) and as the blessed children of Christian parents. We call them to believe that they are God’s saved children if they are depending upon Christ’s blood and righteousness alone. Therefore, we sing hymns together, read Scripture together, pray for requests together. Sproul’s appeal to God’s immutability as the basis for generational blessings is illogical and ill-conceived. God called Abraham to circumcise his descendants everlastingly (Gen. 17:13) yet ceased circumcision under the New Covenant fulfillment (Acts 15).
Overall, Sproul’s argument is from emotion, not revelation. It is no less a manipulation of parental affections to establish infant baptism than the manipulation of one’s emotions to walk an aisle all the way into the baptismal tank. Such arguments are not worthy to establish the validity of a sacrament. Christ institutes Sacraments through revelation, not through emotional appeals to debated issues. Nevertheless, Sproul’s call to the importance of family worship is well taken.*
*Vol. 2: The Reformed Baptist Theological Review Volume 2. 2005 (1) (157–158). Owensboro, KY: Reformed Baptist Theological Review.