Historic Reformed theology and practice have always emphasized the fact that the Lord’s Supper is for repentant sinners who’ve professed faith in Christ. This is why, for example, the Westminster Shorter Catechism says that in order to receive the Lord’s Supper, a person must examine himself of his knowledge to discern the Lord’s body, of his faith to feed upon Him, of his repentance, love, and new obedience (Q/A 97). This wasn’t just written on a whim or without deep thought. Reformed theology and practice in this area is based on, among other texts and doctrines, 1 Corinthians 11:17-34.
In the book Children and the Lord’s Supper, George Knight has a helpful article on this text that explains the historic Reformed position based on exegesis of the passage. I can’t give all the details here, but I can give some of Knight’s conclusions at the end of the article:
Those partaking [in the Lord’s Supper] are doing so in response to God’s invitation (cf. the repeated ‘do this’ in 1 Corinthians 11:24, 25, followed by the offering of the bread and wine which the participates take and eat and drink… ) Babies cannot so partake by doing this themselves.
Those partaking are to do so ‘in remembrance of me [Christ]’ (1 Cor. 11:24-25). Babies cannot so partake ‘in remembrance of me [Christ]’. Furthermore, this remembrance can only truly be done by those who have saving faith.
Those partaking (‘whoever’) are to do so in a ‘worthy manner’ (and not in an ‘unworthy manner,’ 1 Cor. 11:27). They partake worthily when each one ‘examine[s] himself’ (1 Cor. 11:28), and discerns the Lord’s body represented in the Supper (1 Cor. 11:29). Babies cannot fulfill these apostolic requirements for all those who are to partake. Only those who have saving faith can truly fulfill these requirements.
Those partaking are participating in the nurturing of their faith (cf. 1 Cor. 10:16…). The institution of the Lord’s Supper is given to his disciples and it is reiterated by Paul to the church to be practiced in the church by those who have believed and who can be so instructed and warned. Thus faith, by implication, is necessary for those partaking to participate in the nurturing of their faith (cf. WCF 29.7). Therefore, only those who have made a public profession of their faith are to be admitted to the table.
…The result of this analysis of the Lord’s Supper, as it is presented in 1 Corinthians 11:17-34 together with the positive and negative consequences, provide a rather clear reason why the church of the Lord Jesus Christ, in obedience to His Word, has not admitted children to the Lord’s Supper solely on the basis of their baptism and without a profession of faith (p.94-95).
This is a slightly edited summary of Knight’s concluding points. There is more to his discussion, which is worth reading for sure. There’s also more to the discussion when it comes to children and the Lord’s Table. For now, please note that the historic teaching and practice of Reformed churches is based on Scripture, not tradition or expediency.
This book, Children at the Lord’s Supper, is a good resource that includes contributions from Ligon Duncan, Joel Beeke, Derek Thomas (and others). This is a resource that gives further biblical, theological, and historical reasons why Reformed churches require a credible profession of faith before allowing God’s people to the table of the Lord.
Children at the Lord’s Table; ed. Guy Waters and Ligon Duncan (Ross-Shire: Mentor, 2011).
Covenant Presbyterian Church (OPC)
Hammond, WI, 54015