That the Eucharist is to be received with fear and honour
In Leviticus: “But whatever soul shall eat of the flesh of the sacrifice of salvation, which is the Lord's, and his uncleanness is still upon him, that soul shall perish from his people.” Also in the first to the Corinthians: “Whosoever shall eat the bread or drink the cup of the Lord unworthily, shall be guilty of the body and blood of the Lord.”
Source: The Treatises of Cyprian (New Advent)