"Now concerning the Thanksgiving (Eucharist), thus give thanks. First, concerning the cup: We thank you, our Father, for the holy vine of David Your servant, which You made known to us through Jesus Your Servant; to You be the glory for ever. And concerning the broken bread: We thank You, our Father, for the life and knowledge which You made known to us through Jesus Your Servant; to You be the glory for ever. Even as this broken bread was scattered over the hills, and was gathered together and became one, so let Your Church be gathered together from the ends of the earth into Your kingdom; for Yours is the glory and the power through Jesus Christ for ever. But let no one eat or drink of your Thanksgiving (Eucharist), but they who have been baptized into the name of the Lord; for concerning this also the Lord has said, Give not that which is holy to the dogs."
- Didache [The Teaching of the Twelve Apostles]