That’s question 4 in this book:

John S. Hammett. 40 Questions about Baptism and the Lord’s Supper. 40 Questions. Grand Rapids: Kregel, 2015.

(I love the 40 Questions series. It’s clear, concise, and thoughtful.)

So it is proper to baptize a child in, say, a bathtub in a family’s private home? Or to observe the Lord’s Supper when hanging out with a few Christian friends at the beach? Or for a Christian school to practice baptism or the Lord’s Supper in chapel? Here’s how Hammett concludes his answer to the question “Are Baptism and the Lord’s Supper Only for Churches?” (p. 44, formatting added):

Three underlying issues seem to predispose one to advocacy of or opposition to such practices, and thus operate as criteria for decision making on this issue, whether recognized or not.

First is a regulative as opposed to a normative approach to matters of the Christian life. Should we avoid practices not explicitly sanctioned in Scripture (the regulative principle) or should we feel free to engage in practices not explicitly forbidden in Scripture (the normative principle)? Those emphasizing the regulative principle would tend to discourage extra-church observance, while those favoring the normative principle would see it as a matter of Christian freedom.

The second issue is whether one’s vision of the Christian life is primarily individual, focused on an individual’s personal relationship with God, or primarily corporate, with the local church as the appointed context for Christian living. For the latter, observance of baptism or the Lord’s Supper outside the context of the gathered body would seem inappropriate or to lack full meaning, while the former may find more frequent observance than that of the local church a helpful stimulus for their spiritual life.

Most important for this book, the third issue that should shape one’s attitude toward observing the ordinances in contexts outside of the gathered church is one’s understanding of the meaning of these rites. Is there something inherent in the meaning of baptism and the Lord’s Supper that links or at least fits them for church observance? For example, if one aspect of the meaning of baptism is initiation into a local church, it would seem that baptism performed outside the context of a local church would lose that aspect of meaning.

I think Hammett correctly frames the issue, and his book goes on to explain the meaning of baptism and the Lord’s Supper in a way that tightly links them to the church.