The fourth piece of evidence that baptism is administered on the principle of vassal or parental authority:
(d) The oikos (household) formula
Finally, Kline appeals to the New Testament accounts of household baptisms where the household is baptized or brought into the church on the basis of the confession of faith of the parent (Acts 2:38-39; 10:2, 47-48; 11:14; 16:15, 33-34; 18:8; 1 Cor. 1:16; 2 Tim. 1:16; 4:19). The “oikos formula” refers to the recurring statement that “he/she and his/her (whole) household” believed and were baptized. This paedobaptist argument was famously articulated by Joachim Jeremias in the 1960s.
Kline thinks the oikos formula supports the paedobaptist view that the principle of parental authority carries forward into the New Covenant. Of course, there are difficulties with using these texts: (a) we don’t know whether small children were actually present in any of these cases, and (b) since slaves were also members of the Greco-Roman oikos (household), the paedobaptist appeal to the oikos formula may lead to the unwanted conclusion that slaves should also be baptized. Kline recognizes these difficulties, but wishes to makes the following point (BOC, pp. 96-98):
We would simply observe that for the purpose of substantiating the authority principle of covenant administration the precise constituency of the households involved would not need to be determined. Whether or not there were infant children in one case or the other, or slaves in this or that household, households are mentioned along with the central authority figures in these instances, and these households had to consist of somebody in the category of household subordinates. Even with respect to the narrower question of whether parental authority is honored in the administration of the New Covenant, it would not matter whether conclusive evidence could be adduced proving that there were no children in any of these households; for if there were no children, then surely the households consisted of servants; and if it could be shown that servants were received into the church on the basis of the authority principle, it would follow a fortiori that the continuity with Old Testament practice included infants too …
The recurring mention of the household along with the central figure, whether in description of an existing God-fearing community, or in an invitation to salvation, or in an account of the acknowledgment of faith, or in a record of the administration of baptism, can very naturally be interpreted as the terminological reflex of a standard missions policy according to which the covenant community would regularly be enlarged through the accretion of household authority units. Indeed, it seems easier, particularly in the cases of prospective announcements of salvation and evangelistic proclamation (Acts 11:14; 16:31), to account for the recurrence of the appended reference to the household as a statement reflecting administrative policy rather than as a prediction based on a possible general rule that the sovereign soteric operations of the Spirit of God permeate intimate groupings of men. To explain the language of these declarations as meaning that the invitation with its terms was not confined to the householder but was extended to the members of his household, they, too, being invited to salvation on the same condition of faith, seems somewhat artificial; moreover, it would not explain the phenomenon of recurrence.
[Note: I have some additional information on the oikos formula based on Jeremias’s work that I’m trying to upload, but Adobe says the file is corrupted. Hopefully I can resolve the problem by tomorrow.]