WCF 29.4.
Private masses, or receiving this sacrament by a priest, or any other alone; (1 Cor. 10:6) as likewise, the denial of the cup to the people, (Mark 14:23, 1 Cor. 11:25–29) worshipping the elements, the lifting them up, or carrying them about, for adoration, and the reserving them for any pretended religious use; are all contrary to the nature of this sacrament, and to the institution of Christ. (Matt. 15:9)